Bought a phone (Huawei Ascend Y300) 4 months ago from carphone warehouse.
Paid cash and had bought it using my o2 pay as you go sim to upgrade thereby getting it cheaper. I later purchased a monthly o2 contract sim online and swapped it with the payg one.
I was under the impression the phone was unlocked and would take any sim however today 2 new sims arrived from '3'. I popped one in and ther's no signal at all despite being in a good signal area.
Has inserting an o2 sim locked the phone to that network?
Strangely I popped in an old T-mobile sim ive had for years and got a good signal strength from that.
