I swiched my supplier and I had no problems with my previous supplier. I guess because website I used - Tower Utility took care of everything. But logically there shouldn't be any problem.

I had problem with them too so I I used Tower Utility to compare prices. At first I thought that there is no way to find good deal on a website which compare suppliers but now my bills are lower.

I think that you can switch but I am not an expert. I switched my supplier using Tower Utility and I think that they can answer your question. Just contact them and tell them everything. I can recommend them cause my bills are lower now.