Validity of a DIP

Salaam all
We had a DIP with an Islamic Mortgage providing bank. We had agreed on a 5% deposit and 95% finance. The DIP was valid till 12/07/22.

We found a house, made an offer, got accepted. When we talked to the said bank on 01/07/22, we were told that they have stopped the 95% product since May. This means we either come back with a 10% deposit, or lose the deal.

Does that sound legal? Can the bank do this? I was told by them they can as it was a DIP not a formal agreement yet.

Please advise.