They may want to continue to trade with that customer and they don’t really want to have to get into the nuts and bolts of why the customer hasn’t paid.
Or they may find that they have come to the end of the customer relationship, and they just want to outsource the collection to a third party.
There are numerous reasons why people outsource, and all of them are justified. Just be aware that there is a cost to outsourcing collections, so the more you can do in-house, the better for your own bottom line.
But if you decide to outsource, then look for a team that are going to sound and look like your business, but tougher.
There is no point outsourcing to a third party if they are just going to carry on trying to collect payment the same way that you have done, and which hasn’t worked. Their process has to dovetail with your process, so that in the mind of a late-paying customer, this is an escalation and everybody can see that you really are serious about getting paid.
What you should expect from the outsource collection team is a service and a system better than your own, because this is their specialization. You should receive regular reports designed to help you understand what they are doing and achieving. These reports should include the amount of money recovered and updates on debts that have not been paid.
You should also ask for the reports and remittances at intervals that suit you. Whether you need them daily, weekly, or monthly are all sensible options. Keep track of how you work with the collection agency and what results they are getting on your behalf - they should be a natural extension of your team.