no carrier on gm862 after connect

hi can anyone help me

several weeks ago i was able to implement easy gprs for gm862. i was able to use http GET and POST in hyperterminal and was able to communicate with my web server. today as i tried it again after i make a socket dial at#sktd=… it responded CONNECT but after several seconds while i was inputing the http data it always responds with NO CARRIER.i turned off the timeout but it still s the same response.i am using a post paid sim.what seems to be the problem? a few days earlier it was ok… does anyone know?

thanks in advance