One suggestion regarding your post Bekir: can you please make the attached image resoultion higher so that the content can be read easily? I was unable to see what you have captured.
The fact that the IP address does not get renewed anymore may be due a problem with the GPRS subscription you have (e.g. low credit balance). It may be worth giving your service provider a ring on this for a peace of mind. Another thing that comes to mind is hardware problems. If your module is attached to a custom PCB, the problems you are seeing may be due to the hardware itself. If you can briefly talk about the hardware platform you are using, readers may be able to provide further assistance on your problem.