Failure to resolve credit card issue

I received my new gold credit card on the 03/06/2020. I activated it via the FNB ATM that same evening. When I tried to make an online purchase on Takealot, it was rejected as I needed to enter the correct expiry date. My new credit card shows the expiry date as 05/21.I checked my card details via the fnb app and note the expiry date is 31/05/2023. I chatted with Shirley via the online bankers advising her that I think the expiry date on my new credit card was incorrect. Shirley suggested I try enter the expiry as 05/23. If I enter both the date of 05/21 and 05/23 neither work. This means I can't make online purchases as I need to enter the card expiry dates. Shirley advised if neither date works I need to email *** I emailed them on the 03/05/2020. I am still waiting for a response. I am feeling very frustrated that I have to raise a complaint to get this looked into.