Spice Jet Airlines — flight rescheduled and customer care not picking the call

My flight from bangalore to kolkata for 1st may sg 741 have been rescheduled to 1.10am which was originally scheduled on 7.20pm. I cannot take this late night flight and trying to contact customer care to change it to other flight. But no one is picking the call. I am trying since last 1 and half hour and it is really becoming frustrating now. How can spicejet have such poor service