You would "Receive photos of many credit cards"... That, my friend, is the biggest indicator that there is credit card fraud involved. I don't know how close this relation of yours is to you, but I'd personally even take it to the police. They need you to do the postings to not be traced directly to them, they buy stuff online and get it shipped to them, they ask you to use a different zip code to validate the credit card, knowing that most likely the USPS will correct the ZIP upon shipping. And, anyone can claim their company is X. Did you know I own Microsoft, by the way? Look up Microsoft.com and you'll see it's a legit company
Don't get taken by these people, and be happy you thought twice before actually agreeing to be an accessory in a scam. Many people find it the hard way after the fact.