Yes.
and there is a legal entity
Yes, but as I said elsewhere, the only viable way to do that with such a small cost is to use the small claims court and the problem is that its decision is not enforceable using a bailiff and it is trivial to ignore debt collectors and they wouldn?t be interested in such a small debt anyway.
Which is why I was asking if anyone could think of any mechanical way to stop the miscreant from keeping on getting a locksmith to keep changing the lock and we have now confirmed that no one can come up with any legal way of actually preventing him from doing that.
Yes, it is certainly possible to get a court injunction to stop him getting the lock changed by a locksmith, but that wouldn?t be cheap and he is likely to just ignore that and is very unlikely to be jailed if he ignores that with a civil matter.