Capfin my worst nightmare

Capfin my biggest mistake ever I regret the day I app**** for their loan its worse than the loan sharks. Their staff you can call three times a day speak to four different people all of them will give you a different response. I'm trying to invest in a property my loan was declined by the bank because according to capfin I owe them 12000 instead of 6000 when I called requesting the settlement letter they gave me an amount to pay, I have paid the amount and requested that they close the account and give me the letter , now they are coming up with stories that I paid more and they have to refund me but their system is not working they have to contact there finance which will take 24 hours they wont close the account before that and i urgently need a letter with my ID numbers which they are also refusing to give me and they are the ones who gave me the settlement amount they are just full of stories, I don't know what to do I've been calling Capfin since Monday.