RCS not sending Closure Letter in Appropriate time

In April 2020, I requested a settlement letter of which I paid and advised RCS of the payment which was made on time in good standing. I was advised it was received and closure of the account would start and I would have to wait a month for them to close the account. I followed up in the first week of June 2020 as to the Closure Letter I need to give to y bank as proof this account is closed, I was informed two weeks later that there was an outstanding issue and that the closure had missed the date specified, I was told this was resolved and closure started again and would take 36 days, we are no way past this date and now it is the 14th July 2020 and I have still not received the Closure Letter, you can never get to the right department plus more to discuss this issue and they simply keep telling you that the issue has been escalated, but nothing happens. I want my Closure Letter immediately and not when they feel like it now. With all the complaints on here, I am surprised this Financial Institution is still running, as they are a totally unprofessional organisation.