What does illegal activity on a user's profile mean?

[godmodlod]

WARNING! Off-site contact information posted. Most scams occur off-site. Please contact members directly via EpicNPC chat. We do not investigate disputes if you communicate off-site.

I was interested in buying something from Smalldevil, also known as CNLGaming, or at least he used to heavily advertise for them and their Discord server.
Here is his EpicNPC profile, but as you can see, his account has been banned.
About a year ago, I sold something to one of the CNL operators, and the transaction went very smoothly. However, now I’m uncertain whether I should trust them because there’s no additional information about why the account (or its owner) was banned.
While illegal activity doesn’t necessarily mean they scammed anyone, I couldn’t find any proper scam reports against this user, their Discord, or their site. That’s why I wanted to ask: why was this user banned?
I’m aware that if I choose to trade with them now, I won’t be able to file a scam report since the user is no longer active on EpicNPC.

This is the most recent scam report I found about CNLGaming but the user who reported it didn't make a proper report. He most likely got scammed by an impersonator.
Scam Report

 

[EpicNPC]

We requested detailed information about how their topup service worked. We must be able to replicate their method at the listed discounted prices they have posted.

The user was unable to provide this information. We then assume the method they're using is illegal (credit card chargebacks or stolen credit cards) and they are banned for that reason.

 

[godmodlod]

We requested detailed information about how their topup service worked. We must be able to replicate their method at the listed discounted prices they have posted.

The user was unable to provide this information. We then assume the method they're using is illegal (credit card chargebacks or stolen credit cards) and they are banned for that reason.

Sorry for the late response—I haven't used this site in a month. Thanks for the explanation!
Since they're no longer active here, I didn't end up trading with them. Their "business model" is essentially buying items and currency at a low price from other users and reselling them at market value.
I did it once when I sold a Mirror of Kalandra in Path of Exile because I didn't want to handle the sale myself at the time. I probably got around 40–50% less than what I could have made by selling it directly.