Paying via MTN APP is BS!!!!

I'm so angry and disappointed at Mtn. I have paid for my account on the 7th of April 21 via Mtn App. Now my account has been suspended, went to the store Springs mall this morning and I explained to them about my account suspension. They checked on the system and it's showing that I haven't paid. I showed them confirmation of payment on my email. They told me that in order for them to unblock or clear it I have to print out my bank statement showing that I have paid, after showing them a confirmation via my emails. I sent them my bank statement this morning at 10:00am, till now my account is still suspended!!! I called to make a follow-up but they told me they busy with customers they'll attend to me when there's no customer (as if I'm not a customer).

Why would MTN implement something that's not working? Paying via APP must just be cancelled.