How to reach a settlement with the bank on credit cards to avoid collection agencies?

I have credit cards from a bank in the UAE and the limit for both cards is 7500 but the outstanding is 9800.

I asked for a settlement of AED 4000 for both cards, as I paid more than 2 or 3 times the card limit and it's been blocked for more than 3 years.

The collection agent keeps on calling and saying a maximum of 3 installments for 7000 as a settlement but I am not able to afford that amount.

Also, the bank is denying to talk and telling me to contact the collection agency for settlement and the bank is not responsible for this.

Can you please guide me in this?