I had a problem at one point with my card being declined because I spent more than I was allowed to in one day on my debit card - there's some sort of safety feature to limit purchases in a day to 1 or 2k in a day on the card. My wife used the debit card to pay the mortgage, electric, gas, etc. bills online... I drove to Buffalo (over an hour away from me) and bought a kayak as a summer gift to myself - my card was refused as a debit card despite having way more than enough on it. IIRC, I switched over to using it as a credit card and it went through. Compounding matters, as a physics teacher, I occasionally have some powerful magnets in my pocket and had erased the magnetic strip on all my cards... I had to provide plenty of ID as to who I was 🙂