What does my customer have multiple charges showing in there bank account? Will they be charged multiple time?
When a purchase attempt is made it goes to the bank (they check is if funds are available and basic fraud), the bank authorizes it, Visa and Mastercard take the money which causes it to show a pending charge. Then the bank sends the gateway a response that tells us if their CVV matched, address matched. Based on the results, fraud prevention rules determine if we think fraud is involved. At this point, it is declined and it takes about 2-3 days for the money to show back in the purchaser's account. Unfortunately, Visa and Mastercard are quick to take the money but slow to refund it. If the customer attempts to checkout multiple times and has multiple failed attempts it will show multiple pending orders.
If you log in to your gateway account at https://app.2agateway.com/
and go to Reporting > Settlements you can see all the transactions that have completed and charged. If it is a voided transaction, that would indicate that the charge did authorize with the bank but was declined with the gateway since the address or CVV entered did not match the one on file with the bank. So the charge would show pending in their bank account but would not ultimately go through. You will not see an option to refund in the gateway because no money was actually ever transferred to the merchant, so the funds are in bank limbo but should disappear as a pending charge from their account in 2-3 days.
If you want you can change the rules in watch dog, you can go to Manage > Watch Dog > Post Rules. For example, if you want to allow transactions where only the zip code matches then remove P. If you loosen rules you need to be careful to review orders and try to identify potential fraud orders. Fraud orders often use the correct zip with a different address so they can still receive the item. The looser the rules, the higher the risk. So you must determine what's best for your company.