Blackberry Phones ... UK Question.?

My phone is on Orange network, and T-mobile signal comes up sometimes on the screen too. Both of them have been merged purposely to try and create the largest mobile phone company in the UK. I don't have a blackberry however, but my other friends do and they are on 02, and have no problem with signal, and i have problem with signal also with being on orange/t-mobile, and my phone is an LG cookie. I would suggest changing networks, Orange and T-mobile are rubbish at the moment.