Phone number won’t transfer to new iPhone

My previous phone service carrier used a different set of IMEI number instead of my actual phone IMEI. When I transferred and setup my new service with another carrier, I originally provided them with my old phone IMEI and NTP not aware that my IMEI is different than my account#. I ended buying a new cellphone with esim card with the new carrier thinking it will be transferred with no issues. The previous carrier completed the transfer of my old number and I clearly provided the new carrier with the correct account #. I clearly stated to remove my old device IMEI and make sure to use the right account# and they said they did over and over but it’s been 3 weeks they can’t complete the transfer of my old number. Do they need to start the setup all over again? Anyone experienced this type of issue? I thought it would be easy to move to a new carrier.

[Re-Titled by Moderator]