We have started the chargeback process on multiple transactions to the same merchant as unauthorized. The merchant has responded to 7 of the disputes with documentation. The documentation does not match our client's name, address or email but the address was local. We asked the client and he admitted he knew the person and has bought stuff for him from this merchant before but did not authorize these charges. The client also admitted to entering his card information into his friend's phone and think the card information may have been saved on the friends phone.

1) Are we able to deny the claim due to the client admitting he added his card information onto his friends phone, making the phone an access device his friend was able to use?
2) There are 3 charges on the same date rang and with the same merchant that was below our threshold to dispute with the merchant. If we are able to deny the other charges based on the information provided by the client, are we able to deny these smaller charges since they appear to be all tied together to the same situation or do we need proof the client's friend did these specific charges to deny them?

he is stating he did not authorize, you will have a hard time proving otherwise, regardless if he has bought from them in the past.

Especially since the name, address, and email are not your client's.