Cancelling my own visa

I am teaching English on a business M type and want to quit as the company is very deceiving and I don't trust them. In the contract (l assume legally useless as it's a teaching contract and I'm not officially teaching) it says I must give 60 days notice and give them my passport so they can cancel my M type. I don't trust them with my passport and basically want to leave without giving notice. I know this is morally dubious but this company does much worse to its employees. So my question is can I cancel my own business M type without them being involved? and if not and I leave anyway, what is the most they can do? Will there be any way for them to let the PSB know that I deserted them and make it harder to get an entry permit next time, or will this not be possible for them as the contract is not official? Thanks