Unable to Use FaceTime and iMessage

I switched sim cards yesterday, only for a fe mins, but since I put the initial one back I have been getting error msgs like “waiting for activation”. I have already followed the steps I found online such as checking the Date and Time, Turning Off FaceTime and iMessage, restarted the phone, checked with my carrier, waited 24hrs etc. and nothing is working. Sigh. How do I fix this?