Those are not the same thing. The OP was not told they should have done something differently. A friendly warning that somebody had been know to tell lies, or a reminder that somebody might make a fuss if the OP is late for the next lesson could both be construed as helpful. Indeed, more than once,I had somebody make a comment to me when I hadn't noticed the bell go for the next lesson; I took it as them being helpful. It may well be appropriate for the OP to have a quiet word with this TA, but not in such a confrontational way. And I certainly stand by my view that neither is sufficient to warrant an official complaint. Perhaps this person is trying to assert themselves in some way, or perhaps they are just over-inclined to offer unsolicited advice. I don't think we can tell from this. If the OP speaks to the person concerned and incidents continue, then it does start to look like bullying.