H'mm I suppose you could say it was illegal due to the telephony act. But I wouldn't think it would get very far.
I wouldn't worry about the MOR game. I wouldn't get childish and start firing them back in. Best people to have a chat with would be the SRG air traffic inspectors. Or try phoning a CAA staff examiner, they have absolutely no authority at all with all things air traffic but they know the rule book inside out. They have lots of mates they can have a chat with. And having heard a very one way discussion between a single digit Exam callsign and a SATCO about the level of service of his unit it was clinical and very scary.
If you have the date and time when the person was refused wx because they weren't landing at the airport I would use that as your opening card. The inspectors will not be happy with that at all, and will be more receptive to your other complaints after being given a good hard event which they can run with.