Settlement Letter delays

I called RCS on Monday the 29th July 2019 asking for a settlement letter for my Builders account, I was then told it takes about 24 hours to receive it. I made a follow up on Tuesday the 30th July, I was again told that it is actually 48 hours not 24 hours. I made another follow up on Wednesday the 31st July, since 48 hours had passed, I was told that I must still wait. An agent then called me later on the day and advised that I will only get my settlement letter after 5 days since a debit order just went off, I explained the urgency of the matter to her and she then said she has escalated the matter and I should get the letter by later today or tomorrow. What could be so difficult in issuing a settlement letter?