Cheque returned after registration of land

Hello Sir/madam

Land Sale deed was executed and cheque was issed after registration for payment.

Cheque was bouced due to signature mismatch now client is saying will trasfer through online, But in sale deed chequen number and date is mentioned.

what is the process??  is there any document like MOM for change of transaction of payment,

legally there should not be any litgation due to this transaction infuture kindly advice.

thanks 

Prasad