Handed over even though I paid them and sent them Proof of Payment

I have been with Discovery and Discovery related institutions for a while now, although it has not been all smooth sailing, the service has been decent at most times. I made the mistake of making use of their Apple Watch benefit. While it was smooth sailing when it was calculating the points correctly but towards the end, it could not register an 80% workout, and after informing a few times, I just gave up. This meant that I had to pay and I did pay, I was however handed over to their attorneys. I paid them on the 20th of March and sent through a proof of payment when it still wasn't reflecting a week later. There was no instruction as to what to use as reference so I used my Vitality membership number. Aside from being handed over, I can no longer make use of the Apple watch benefit as a result, my credit record is affected, and when I phoned earlier I was informed that the investigation was still open, and that the investigator will phone me soon, a couple of hours later and still no phone call.