Be nice – but don’t be a push over.
to prove bullying – you have to prove that this is a pattern of behavior that serves no legitimate purpose except to upset or harass you. To do that – you need to keep a log and document what is happening. You do not need to respond. In fact – it’s better if you don’t.
The bad news is – bullying is repetitive and gets repeated. That’s the nature of bullying. The good news is that bullying is repetitive and that means – you can plan your response.
This is one of the things I am asked about – a lot. What comebacks can a person say to a bully that will make the bullying stop. There are LOTS of good options.