Old number still showing as transfer in progress

I have had my account and number for a month or so and all good. I then transferred my father’s number to my  group account . His phone is working fine on his transferred number and texts and calls are all registered fine in the app however I still shows his old number and “transfer in progress “ 3 weeks after the transfer has completed. I have deleted and reinstalled app and called support but all they said was wait a day or two and they couldn’t see a problem. Sooo what do I do ?