Data purchase constant error message

I took my car to be washed bought lunch and 1 gb data, have not been able to up load it, gives error message unknown error. I phone and a gentleman answers who is rude in helpful and says it is not his problem. I am not only stuck with an invalid voucher costing over 100rands, but so frustrated I will not wash my cars there shop there or use their services in any way. He should get a course on how to deal with customers