I Have Applied For A Mortgage Loan And Got Sanctioned And I Canceled It

I had applied for a mortgage loan in bank and it got sanctioned. But the sanctioned loan money was very less than what I had applied and also interest was very high . before I could get the loan sanctioned letter from bank they got the agreement signed and took the cheques telling its month end. but I didn't accept the sanctioned letter and dint sign in sanction letter. And I informed the bank in charge telling to cancel my loan. and I also sent mail and registered post to cancel my loan. but the bank in charge is asking cancellation charges. please help me