invalid voucher

this is the worst services i have ever got from a bank institution so far. i report a query they take lately to make things wors they don't even have a tollfree for queries. i bought a R50 voucher using my African bank app and its a supabet voucher, so when trying to use it gives me an error code and i tried to report my problem at the branch they couldn't asset me so they called the call center and the agent said they will get back to me within 48 hours and never did oh and this voucher was bought 3 months back on the 28th of April 2023 and i still can't use it by now . so after the 48 hours off waiting for the call I want back inside the branch to complain that i was not contacted by the call center all they did was call them back and i spoke to an agent again and it was not the someone so meaning i had to explain myself to them again after doing that thinking that i will be asset off which not all she could say is that on her side she can see that they did login a query about this so she will try and escalated to the relevant department and that i was going to be given a call asap and no one call after a week i want back to the branch and i even told the lady helping me that this worst Servies i had ever got from a bank she just kept quiet and then she tells me that she is going to send a email to complains and she gave me a ref no and told me i was going to get a call within 7days off which but the time they call driving and i asked the agent to give me a call in an hours' time off which i think this is how they train their agents that after receiving a call or talking to a client if they know or think they can't help you is to just tell you that they will you call back and never do that I think that is how they handle queries. because now it's the 3rd month still not help, and they don't want to refund me for that matter.