138 negotiable instrument act

sir, i have filled a case against a person the case as the person is known to us from 20 years almost my father and his father are working in a same company and he want to sell his house which is on the name of his mother he said he will get the power of attorney on his name for sale of the property, so we made an agreement in which he has writteen that he is selling this property which belong to his mother and she has given him the authorty to sale the property. he sighned and given to us and then we sighned and the two of our witnesses has signed and then we have given him the down payment of the property.after few months he stoped reponding about the property so we said him to give back our money ,for that he has given us a cheque and as we presented that cheque to the bank it came reture with the notification of account closed,our case has started but i want to ask that the party has give us the cheque that belong to his company not his individual account at the time of bank witnesses the acussed lawyer has asked the bank witness that does the cheque belong to the accuded individually or his company he said that the cheque is belong to his company, that might create a problem to may case if yes then what should i do at this time???