Is it illegal to use the transfer market? Why was I banned and can't get answer?

Guys....

I have played FIFA/EAFC every year since FIFA 98, and FIFA Ultimate Team since 2009. So I have a lot of experience using the transfer market in FUT, and I spend a lot of time and effort on trading in the transfer market, because this is what the transfer market is for, right? To trade....

I want to have the best team possible, like most players do, and trading in the transfer market is my best way of getting that, and for me it's a matter of HONOR to get my team the old school RTG-way, without spending ANY real money at all, not through EA shop or any third-party coin dealers. I consider myself a hardcore player, and I usually win more matches than I lose in FUT champs every weekend...

Suddenly, for the first time ever, I was banned, and received the mail that I linked to this post. I have appealed my ban 2 TIMES in the EA help section, but my ban was declined without anyone even bothering to give me an answer as to WHY my appeal was declined. I am innocent and did NOTHING wrong. NOTHING WRONG. I did not break ANY rules or terms of service. Was I banned because I was using the transfer market like I always do? Was it because I sold a bunch of Argentinian LPF(ARG1) silver cards for 3000 coins when they suddenly went up in price due to the World Tour Argentina SBC? Was I banned because I buy Team of the Week cards close to discard price, and sell them for slightly more than that? Was I banned for selling consumables for slightly more than I bought them for? I can't even get an answer as to why I was banned, and none of my transfer market activity should be causing a ban...

Is it now criminal to use the transfer market? Can some EA employee please manually investigate my case, my account, and my transfer market activity, so I can get unbanned again? Or at least talk to me and tell me WHY I was banned for something I did not do?

Someone please help me.... I don't want to end my journey here, after sticking with this franchise for more than 26 years...