Cheque bounce as a guarantor (without any Signature)

Dear Sir/Madam, Someone gives me legal notice in check bounce case as a guarantor, I did not sign anything. My father gives him a cheque with his signature and later on, my Father stopped that check in the bank with remarks (checkbook lost). after more than 1 year that person gives us legal notice and demand for the money. My father give him a blank cheque and he writes the amount 4 times more and date, name itself. He named me as a guarantor and produced some more people against me like I give a guarantee in front of them. What I can do? I did not sign anything as a guarantor and court summon me under section 138?