Bad customer service

I have a bought airtime at Pick ‘n Pay liquor the Marc, when I was loading it kept on saying that it Valid went back to the shop and spoke to Sbongiseni who was rude told me that “ what must he do there’s nothing he can do I must call mtn ask them why is the airtime not working which I did while in the store but which they told me that the voucher is invalid, he then told us to go ask for a manager because he has nothing to do with airtime I got to the store requested a manager who didn’t bother to come see us, Andile was not even interested in our matter she never even ask what was our issue or problem, only 1 lady by the name of Shimani tried assisting which she also didn’t know how to resolve and told us they have been having the same problem.