Advertising "problems"

Hi all

Just signed up here, been a gite owner in the Creuse for 10 years now and have advertised all over the place, some good, some bad, some free and some expensive. I signed up for a free trial with a company called UPPS a while ago, had a few viewings but no enquiries so when the "free" period ended I asked them to remove our listing from their website. They refused to do this and have now started to send invoices and treatening emails. Has anyone else had experience, good or bad with these people?