A common payment support call we receive is:
“Our customer says we charged their card twice, but I only see we charged them once when I check their payment history in Kennel Connection. They even showed us a screenshot of two charges. Your system ran the card twice.”
In nearly every case, this is not caused by the processor or the software. It is caused by a local network interruption at the merchant location.
Understanding what actually happens will help you prevent duplicate charges and avoid unnecessary disputes.
What Really Happens During a “Duplicate” Charge
Here’s the typical scenario:
- You run the card.
- The Clover terminal or software appears to freeze or times out.
- You do not receive an approval or decline response.
- The invoice still shows unpaid.
- You run the card again.
- You receive an approval and the invoice is now showing paid, however the customer is charged twice.
From the merchant’s perspective, it looks like the first attempt failed as this invoice still shows unpaid.
But here’s what actually occurred:
- The transaction was successfully sent to the processor.
- The processor approved it.
- The approval response was attempting to return to your system.
- Your local internet connection dropped or timed out before the response came back.
The processor or software cannot create a duplicate transaction on its own. A processor only processes what it receives. If two charges appear, it means two authorization requests were submitted.
Why This Is a Network Issue and Not a Processor/Software Issue
When a timeout occurs, it is almost always caused by:
- Unstable Wi-Fi
- Router interruptions
- Firewall resets
- ISP latency
- Weak signal strength
- Switching between networks mid-transaction
The first transaction is already completed on the processor side.
But because your system never received the approval message, the software along with the merchant assumes the payment did not go through. This is why the invoice may still show as unpaid.
Why the Invoice Shows “Unpaid” Even Though the Card Was Charged
This part confuses many merchants.
When the approval response does not return to the software:
- The processor sends the authorization request to the customers bank, it approves and the processor shows the transaction as approved.
- The funds are pending on the customer’s card.
- But the software never receives confirmation.
- Therefore, it does not mark the invoice as paid.
So from your perspective:
- The invoice looks open.
- You assume the card did not process.
- You rerun it.
- Now there are two successful authorizations but only one successful paid invoice in Kennel Connection.
The customer calls a few days later and claims you charged their card twice.
The processor did not duplicate the charge.
The system simply never received confirmation of the first approval.
How to Prevent Duplicate Charges
1. If You Do Not Receive a Response — Do Not Immediately Reprocess
Before running the card again:
- Log into the Cardpointe gateway
- Check the transaction log: Reporting > Transactions
- Confirm whether an approval already occurred.
You can also call us at Kennel Connection to confirm if the payment was successful.
If it shows approved but the invoice still shows open and unpaid— do not rerun the card.
Instead, manually apply the payment to the invoice if needed.
2. Improve Network Stability
Since this is typically a connectivity issue:
- Use hardwired internet when possible (supported on the Clover Mini).
- Avoid processing on unstable guest Wi-Fi.
- Reboot routers regularly.
- Ensure your firewall is not interrupting outbound connections.
- Avoid switching networks during transactions.
Stable internet = stable payment confirmations.
3. End-of-Day Review
If you suspect a duplicate occurred:
- Review your daily batch in Cardpointe before settlement.
- Identify duplicate authorizations. (You will typically see two transactions back-to-back for the same amount and on the same last 4 digits of the card)
- Void one of the duplicates in Cardpointe before batch close if still possible. Simply select the transaction ID and then select VOID. This cancels the transaction so it will not be processed or submitted with your daily batch settlement.
Voiding same day prevents:
- Customer confusion (catching it before the customer does and correcting it)
- Refund processing delays
- Potential disputes
Why This Matters
Duplicate transactions can lead to:
- Customer frustration
- Refund requests
- Chargebacks
- Negative reviews
- Loss of trust
Most importantly:
These situations are preventable.
Understanding that this is a local connectivity issue and not a processor error allows you to respond correctly in the moment and avoid doubling a charge.
The Bottom Line
If two transactions exist, two authorizations were sent.
Processors do not generate extra charges on their own.
When a timeout occurs and the invoice shows unpaid, always verify on the backend before reprocessing, or check at the end of the business day or when time permits.
A few extra seconds of confirmation can prevent unnecessary disputes and protect your customer relationships.
