Some years ago, we were pursued by debt collectors for a very dubious debt. I wrote to them asking to provide clear proof or to leave us alone. I said that there would be charges for dealing with their correspondence and, if necessary, recovery via the courts. They wrote again in unspecific but threatening terms. I replied asking for detail and enclosing two invoices to them for £15 each. The first invoice said: “to receipt, consideration, rejection and filing of your unspecific but threatening letter of date…” The second invoice said: “to necessary reply to your unspecific but threatening letter of date…” After three cycles, I took them to small claims track of the county court and was awarded and received £90 plus costs.