A representment is in regard to a chargeback that has been filed by a merchant's customer. 

Chargeback representment is the process through which merchants can submit evidence to prove that a chargeback is illegitimate. The issuing bank will evaluate the evidence provided and, if they find it compelling, reverse the chargeback. 

(This is an example of what a representment will look like in the nexio dashboard)

The merchant will need to stay in contact with the chargeback department and the issuing bank.