NWU HAS NOT SENT me my certificate

I was to graduate on the 8th of April, however could not make it so I requested to graduate in absentia. I emailed the graduation department and they emailed me back with bank details so that I can deposit the absentia and courier fee. I played the amount on the 5th of March and emailed my receipt and courier address. The graduation department emailed a confirmation of my payment and ourrier address, they also request my cell number which I gave they also emailed and said I would receive my certificate after the 17th of April. However it has been well over a month since graduation and I have not received my certificate. When I called I was told that i need to resend my proof of payment because they could not find it. I was also told that they were having a backlog. This is very unprofessional. First of all they are wasting my time and second they can't find most of my emails that I sent them which means they are disorganized. Please do what you are supposed to. I need my certificate now please.