that's normal. it should be agreed by both parties before tenancy.

2 methods:

a) use deposit to pay last 2 months' rental. not favorable to landlord in case shit happens to the property, e.g. need cleaning, repair, etc.

b) continue to pay yourself the last 2 months' rental. after landlord satisfied, he/she should pay back the deposit.

being a good tenant before leaving, there shouldnt be issue for landlord to refund the deposits (2.5 mths)