Edgars account paid-up letter.

Am so frustrated with the service I received today- all I needed was to be sent a paid-up letter but none could help me. I was sent from pillar to post as they could not find my details on their system or with Nimble - I settled my account in early 2020, account no:*** card no:*** and requested the paid-up letter which was not sent- requested again in October 2020 and still has not received it till now. I was given the following numbers but did not get any solution-***;***;***;***. The last number given, *** belonged to Transunion. I have sent an e-mail as well. I really need this report to improve my credit profile.