Request of proof of payment

I have been requesting for proof of payments for some months from African Bank, I called customer service and they referred me to the nearest branch, I went the couple of times and they told me to call head office which I also did but have been sent from pillar to post with just a proof of payment from my bank account that I have with them, instead of getting help they are just making me to run around, that is unprofessional how they are treating me as their loyal client .