*********** staff bad service and ***** against my account

I have signed up with Best internet who signed me up with a 3rd party company for my wifi plug and play. They advised that it will be 399 per month I joined end Feb which the agent explained that it will be pro rata end of March a double deduction was made of 798 when I called I was advised to send all my personal documents which I did this included the payment details, I was promised a refund of 399 as the account is only for 399 per month, this is a month to month contract Today I still haven't received feedback or a response when I called again now I was informed that the 798 is for 2 months April advance This is not what was explained to me and this is not what I have signed up for What if I want to cancel April all I want is my money back the premium is for 399 and not 798 and I definitely did not agree to an advance to be taken from my account this is ***** for taking money from someones account without their knowledge The service I got is pathetic bad bad service *********** staff I will not ask anyone to join them sies I just want my refund I have never agreed to a 798 payment