Would a e-commence website with credit card checkout page likely have access to who the merchant processor is on that website?

I am trying to collect on a judgment on a person who is using a 3rd party e-commence website platform as a cloud service. I am wondering if this 3rd party company should know the merchant processor he is using?

In my opinion, they are playing dumb and saying he has no idea who it is.

I work in IT and from my limited knowledge on this subject, I am thinking they should know this information, although I am not a web designer or programmer so I am not 100% sure.

Can anyone confirm or refute if a e-commence cloud website platform where you are entering the credit card during a checkout process should know which company is processing that credit card? Even if its just by an API plugin information or a IP address its being sent to, etc...