Is reverse proxy and forward proxy the best way to proceed

I apologise if I have posted this in the wrong area.

I have been asked to provide a payment solution for a client of mine that I need some help with. They currently sell products that their card processor doesn’t approve of so have created a website selling something similar to get approval for a merchant account, they then manually process the card payments from the non-approved website so as to not alert the merchant provider of what is being sold. I fully understand that this is not the best way to conduct business but it is not illegal as it is simply against the terms and conditions of the merchant provider. My client has asked me to come up with a solution that will enable them to process transactions automatically like any normal ecommerce business, but not letting the merchant provider know what is happeneing. Would the following work:

Server A = non-approved website Server B = approved website

The customer places order on Server A which uses forward proxy to Server B to pass the payment information to the merchant provider, the merchant provider then gives the result to Server B whch then uses reverse proxy to give the result to Server A.