SIM900 wont respond


My SIM900 module that was working till yesterday stopped communicating via my arduino uno board from today. The same setup, wiring etc were used. This is truly a bit mind boggling. I was infact able to connect it using the M2M Module tester yesterday and today it says that "invalid or no response".

I rechecked my wiring and sketch and all seems to be good. I am also able to call the SIM900 and it beebs showing that the call gets connected.

Its like i have been locked out of the SIM900 module. I am also unable to set the baud rate of the SIM900 module because I am unable to connect to it.

Any help is much appreciated as I am behind this for the last two days!..