SERVICE BOND - COMING OUT?

I have signed a service bond for 4 years in my present company for a surety of 3 lac rupees. I have surrendered my origiunal degree certificate and high school certificates to the management.I have retained provisional degree certificate, all semester marksheet with me. I have salary backlog upto 2 months. Can I join other companies if I want to ? Is there any way to get my certificates without paying money? Already 2 years are over in my bond period. Please help