Paid up letter request

I paid up my account with Avon last year February 2019 called them to confirm that they have received the payment, wich was confirmed, to my surprise I app**** for a mortgage and it has been pending requesting a paid up latter, I've called them and they promised to send it to me, I still haven't received anything, and if I don't send the latter today my application will be declined, I'm so hurt by this service in getting from Avon, they are destroying my life