If the account/customer name matches with the lead company name ideally the lead should be converted to a contact as that's the best way to manage contacts within a customer account. In order to accomplish that, you would have to work with your SFDC team to set up a mechanism to either convert these leads at the point of entry if there is a company/account match or you can do it after the fact, by providing a list of these leads and their matching account IDs and the SFDC team can do a batch update.