VERY BAD SERVICE/ NOT UPDATING PAYMENT

So Mr Price for the last 5 + years I have been paying you every month via eft, same day maybe a day here and there out but 99% the same day. 25th of each month. So the second of May I wanted to buy a pants because mine tore at work, asked them to check my available credit, sorry mam you havent paid, (Balfour Park shopping centre). Showed them I already paid on the 25th of April, phoned them from the store, sorry we have issues with our eft system, plse fax the proof, went up to postnet (costing me money), to print the proof and the proof was faxed from the store twice!!!! So again yesterday the 12th of May I went to Mr Price Festival Mall to get something again, AND AGAIN SORRY YOU HAVENT PAID!!! Obviously wasting MY PETROL AND TIME shopping for nothing, you're call centre couldnt do anything. Feeling like an absolute fool I had to walk out there with nothing!!!!!! I have been a loyal client for years and years and this is what you guys do!!!. So I have decided to pay my account up to date and close it, I have been humiliated enough now!!! 17 DAYS after I have paid and it still has not been updated, surely if you received the proof you can update it?????