Regarding Swith Over Of Job

I work for a software company. I have been over burdened and paid late during the month also. Recently one of the senior manager resigned and wanted to join the rival company and offered his team the same oppurtunity. Since I found my future not secured after the senior manager leaves I decided to go along with his offer. This decission was taken by other senior colleagues of mine too. And it resulted in 5 senior people resigning at one moment and presumed to be joining the rival company. Now the current company is charging us of conspiracy with the motive of destroying the company. This caused a lot of headache cause of which we resigned with immediate effect and did not serve the notice period either. They have send a legal notice asking to resume on work with immediate effect and not to join the rival company. I had signed a contract with the current company which is already expired and they have not renewed it. But with the increment letters they have been mentioning that ''the terms and conditions are the same as mentioned in the contract''. The new employer is supporting us right now but may not do so in future. Currently they are ready to bare the legal expenses but what If i leave the new company in future. Please advice.