Mweb's impossible paperwork conundrum

I am moving house, and found a convenient, or so I thought, option on the mweb site for moving house, in which they are supposed to arrange and facilitate the moving of your service to the new address. I got a call back and the agent on the phone told me that everything was sorted out. A week later I get an sms saying that I need to provide proof of address in order for the move to happen. How are you supposed to provide a proof of address for a house that you do not yet live in? Much time wasted and no solution available, just platitudes. No one interested in solving the problem or offering solutions. And their agents are not allowed to provide contact details for management. Very sad state of affairs. I suggest not using these idiots.