Misuse of cheque.

a blank cheque was issued to the complainant after the evidence on record and has held that if a blank cheque is issued by any person and amount payable is not mentioned it does not constitute a cheque and, therefore, the penal provisions of Section 138 of the said Act are not attracted

It is presumed that issuance of blank cheque with signaure  empowers or give authority  to payee to fill the blanks so take other defence rather the writing on cheque.

You have to rebut the allegations by properly challenging it, though the other issues have been written by the complainant, you can send for handwriting experts opinion to know about the age of ink of other contents and that of the signature.The question of legally liable debt is to be concentrated upon strongly.