I have a secure Visa card and I knew I was running out of credit on it but I was sure I had enough to cover my purchase.

So the total at Walmart is $40. I tap the visa card and it only approves partially, says $22 balance remaining. I thought that was odd, I paid $22 with my mastercard.

When I got home I went online and checked my Visa transactions thinking there would be an overdraft fee but the Walmart transaction was not recorded at all, it's not in pending nor in completed transactions and I still have over $100 remaining credit. I checked my mastercard account and it only charged me $22. For some reason it looks like I got $18 free from Walmart?