help with ARN number??

Good day

I have been in a tricky situation now for over 2 weeks and this is because FNB and their consultants are unaware of what I have been requesting. I am expecting money to be transferred from an overseas company into my FNB account. The sender of the money sent me an ARN number that would help me track these funds and was mentioned that my bank could do this for me. I have been to 2 different FNB Branches and not a single person knows what an ARN number is. Forex department transferred me to so many different places and still no answer. I am losing hope so if anyone knows how to get this sorted on this platform please do make contact with me. It would be appreciated.

Thanks Waylan