N Power Question

Sharpies_2

Hi!

First time poster, long time reader.
I moved into a new place in March and found that the gas was supplied by N Power business. Immediately signing up for an N Power dual fuel deal I was told that I'd not need to contact N Power Business about the move as the N Power residential would handle that for me. So far so good, right? However, having started paying direct debits for around £35 a month last month for gas, I've now recieved a bill through from N Power business from the period of March 21st to May 13th for £136.00. As there's two of living there and it's been pretty warm we've not used the gas that much for heating (mainly for heating water) and are obviously out all day. This just seems to be a rather high amount for under two months? If I feel this is wrong is there anywhere to appeal to? Apologies if this is a stupid question - just in previous properties I've always paid by Direct Debit before (as I'm doing now with N Power) and can't remember having to pay out this amount before. Also, as it's a dual fuel deal, should I not be making one payment overall a month rather than two separate ones? Hope somebody can help and thanks for your time!