I've just upgraded my contract with T mobile via a third party provider (Phones4U), and this was only due to this being the only way I could 100% guarantee that I could keep my number. Unfortunately this means I still have to deal with the very poor signal coverage in my flat, and at work. My advice would be to anyone that's considering entering into a new contract with this company to not bother, and to shop around for better alternatives. The fact that T mobile have just been voted the worst mobile phone company for the second consecutive year running (Google this for details) based on consumers experiences also indicates significant cause for concern. So, in this case listen to the majority and don't do it!!
To reply as a company, please log in to your business account.