Exclamation [Q] Only connecting to 3G, Please Help

Ok I have a Galaxy S3 I9305, ive tried many radios and basebands but cant get my phone to get connected to the 2G GPRS service, I live in a very poor 3G area... My nexus 4 connects ok, ive tried *#*#4636#*#* and set it to GSM only but it just disconnects and get no service whatsoever, it happens with every network

Any help would be deeply appreciated

Thank you

Update: Turns out an O2 mast has failed in my area and is not working, checked my dads iPhone and has the same 3G only issue... Too coincidental since I just bought the S3

Hopefully they'll fix mast soon