[Resolved]  IDBI Home Loan — allotted Mortgage loan Instead of HOme Loan

HI,
I have applied for Home loan top up at IDBI bank pune, processed everything according to home loan. got sanction letter as home loan top up. amount got disbursed.. got welcome letter of home loan but bank has to say their system shows its a mortgage loan and not providing me interest certificate. and when asked them its IDBI mistakenly entered loan scheme as mortgage but they are giving very slow and unwilling response with irresponsible statements.
I have all support documents. Please suggest how to deal with thisl.