Concur with WHBM.
As far as I am aware, the aerodrome authority can stop an aircraft departing due financial restraints, but they cannot stop it from landing for that reason.
Addiitionally, if they intend to impound or put a lien upon an aircraft, they are legally obliged to infrom the aircraft operator in writing and obtain a written acknowledgement, (this can be done by fax).
Sounds like a lot of inexperienced chickens running around the roost at DSA Management.