I have a prepaid number and activated an eSIM but it gave me a new number and plan (T.T)

I’ve had a Tmobile prepaid number for YEARS and when I went to activate the eSIM feature it never asked to import an existing line nor link an account. I followed the set up as it indicated on the app and it gave me a new number and plan. I’ve been trying to port my existing number to this new plan since I have credits on that account but to no avail. I am currently traveling so calling is imposible for me. (T.T)