The same thing happened to me once because of a required check to confirm I was human rather than a bot that I somehow missed. I contacted the group and requested another opportunity then tried again. It turned out there was a welcome thread needing a math answer posted. Luckily it was only simple addition since numbers aren't my strength. Just contact the groups and ask what they say. We can't know the reason for your removal but they will.
I'm wondering why anyone gets removed from TG groups without breaking rules. Being very new there I still don't know how everything works. I entered a few seller communities just to observe conversations before making any purchases, basically to review the sellers, yet I keep getting kicked out. At one stage I showed my actual name until told to switch it and then did so. I hardly ever comment at all. Could that be the cause? Any suggestions would help. Thanks!