I didn't think the first charge would allow that to happen...

I have a secured loan on my home which is currently in arrears (the company say arrears of £9000) but this is made up in part with excessive charges, compund interest, visits from 'mortgage counsellors', etc.My first charge (mortgage) is up to date and never been in arrears.The second charge is threatening litigation, reposession, etc. What is the worst that they can actually do? My home is in Scotland.Thanks for any advice.