Credit card limit increase takes 15 days or more to be finalised

I sent signed documents for a credit limit increase with FNB on 13 May 2021 to which I was advised processing would be completed within 3 to 5 working days. I followed up with the bank on 21 May 2021 and was advised to enquire on 24 May 2021 as they application was being finalised. When I called on the 25th of May 2021, I was told that my account needed to be unblocked from MTH Status to which I sent forms on the same day. Today the 27th of May 2021, I have just been informed to wait an additional 3 to 5 working days for them to resolve my issue. Why doesn't FNB just mention upfront that their process takes more than 15 working days to close an increase application instead of taking me from pillar to post and lying. I've been with FNB for a almost 10 years now but it seems they just don't assist clients. The only time you can expect them to action anything is when they deduct money from your account but the service seems to be getting worse by the day.