Useless shop couldn't help me

2day I went to usave in mooki street Orlando east soweto to buy a 3 loaf of bread nd cold drink, it costed me R60, I was using my wife's debit card to do the transaction when a cashier told me that I can not pay with the debit card, if ever it was a credit card I'd understand why am I not allowed to use it, I really fail to understand this bull****, it's best this store to move out of Orlando east and take it to the suburbs with too much rules, I've never seen such things in other shoprite stores, I even asked the manager to show me were is it written in black n white, she couldn't prove her statement to really show how useless they are, retail stores has its own rules written in black n white, not a person telling me her own rule as if she's running a tuck shop, I won't stand for this ****, if you can't get helped Going to shop their, whats the purpose of having this usave in Orlando.