Oh, and I doubt that "just" his debt was sold. Likely, the club sold their entire book of overdue bills to the company, and he's one of many.
Think of it this way - the typical lawyer is going to charge $200 per hour (going from top of my head here, so feel free to correct me). It'll take them 5+ hours to even draft a letter (research time is included in that). So, if the bill is even close to what the lawyers will charge, you can forget about them actively trying to collect.