Well if they are a large company and after you for "unfair competition" you should have an idea by now of exactly what it concerns. Maybe your advertising was against the competition laws or your AGBS (general terms and conditions of trade) were not 100% conform to current law. Or maybe you held a "sale" without adhering to the legal notices required or whatever. In any of those cases I would imagine the laws are not at all negotiable (i.e incredibly rigid as they are in Germany) and the question is only what fine should be levied and how the remedy can be enforced so that it does not happen again. Ignorance of competion laws would be of course no argument.

in any case good luck !

Cheers
cosplay