Paid up letter nightmares

I'm frustrated by the service I get from wonga, I settled my account on the 27/06/2020 iv been waiting for a paid up till today, I gave your team a call after receiving a wrong paid up letter, they required proof of payment, I emailed it and they said they will take it up with the finance team and il receive the paid up letter in 48 hours.. I'm still without it and my wonga account hasn't been update... I'm in need of the paid up letter asap as my things are on hold cause of it.. Some assistance would be highly appreciated