Can not connect to the BIS?

[uluchatip]

I have blackberry bold 9700 since december 2009 and i have no connection problem to the BIS untill this month.
The edge writen in small letter and i do not have BIS connection.I can not send or receive email, can not use blackberry messenger etc..
When this problem accure firstly i send my phone to blackberry service and they said that there is no problem in my device so i call my mobile network service and
there is no problem with it.
They try to cancel my blackberry account to create new one to solve the problem but they could not do it because according to them my device registrated to another mobile network.
I bought my blackberry from england which is a sim-free device and i use it in turkey.My service provider is Turkcell. ,
What can i do to solve this problem.According to turckcell (my mobille network provider) my device should unregistrated and then create new registration as it is a new one but there is no other network provider that i registrated.
I tried every method that wrote in forums.. try to reboot, try to register from Host Routing Table, wipe and upgrade the OS. When i talked with the RIM they said that my network provider should fix it, but according to my provider it is a problem with RIM. Also i send my phone to blackberry service but they saif that there is no problem with my device.
What can i do to solve this problem.Can imei and pin change work. Can i exchange the imei and pin with my old bb. İf i can how.. Please help me to find a way to connect BIS