Struggling to get assistance

If I could give no stars I would. I have been struggling for a year to get my Natis for the caravan which I bought. Even after paying it off they still debited my account. So they owe me money aswell. My bank gave me a number to phone and it doesn't exists . So I googled a number and they put me through from one person to the other and not helping me at all and then threw the phone down in my ear. Please contact me for further information *** or ***