Problem is the same in Sri Lanka with Dialog and Mobitel.
I have an iPad mini and everything was fine for me until I updated it to iOS 8.1 (I think directly from 8.0.1, not sure I got 8.0.2)
Since iOS 8.1 my iPad has the same issues described on this thread :
- No service 98% of the time unless I do a switch-off, shut off localize my device... where the problem is fixed for about 5 minutes.
- My iPad has trouble reaching the Wifi networks (though available for my other apple devices)
- When on wifi, Internet is very slow
- + additional weird comportments : apps self starting of shuting down, self launching of "exposé" (idem double tap on home button), keyboard not reactive and sometimes displaying characters that I did not hit
So definitely 8.1 is not the solution, but the beginning of the headache for some other users and I find it very annoying.
Since 2 years, I'm constantly facing issues with my iDevices while I had always been pro-Apple because it was reliable!!!
My iPhone 5S is back to customer service because battery was swollen and broke the screen, MBA battery/alimentation issues (currently at customer service, while a certified Apple Service center already made me change the battery + the charger on my own expenses), iPhone 5 over-heating battery and trouble with iOS 8.1 as well (same as addtional weird comportments listed above), iMac 27, HDD and alimentation replaced...