Unhappy service

I had a bad experience with a driver yesterday at 12 h15. I had received a voucher from Uber eats valued R80 for minimum purchase of a R100. I am still new using uber I started using it in December. I told him I am new and at the time I was going to pay card with no knowledge that one can only purchase with cash. He said I can make a voucher so that he can collect the cash. He declined the sale after leaving and said I had not paid. I thought he would rectify the payment when he arrived at the store like he said he would. Instead he thanked me for the tip . I am still owing UberEats I do see with the message that I need to pay with my next order. Why did the driver not tell me that I can pay with my next order? Why would I tip a driver R60 when I owe UberEats? This is not professional. He should have at least been honest with me. Now I still need to pay for Sunday's order and he took R60 on top of that.