FNB Customer care

I've got a virtual credit card from FNB. There was unauthorised transaction (not approved on the FNB app) that happened on 20 April 2024 and I open a ***** case(***). I gave them 30 days to investigate and after not receiving any feedback I followed up from my side. I was just told that a refute letter wad sent to me. I told them that I did not received such a letter. In short this was escalated 4 times and I still haven't received the letter. It is now 52 days after the ***** case was opened. I've logged a complaint (Ref.on the app on 3 June and also have not received any assistance from FNB. Also to use the secure chat platform from FNB is the most frustrating service I've ever used and trying to get hold of them on a telephone line you just hold on forever and nobody is answering.