Can you sue them? People pretend it’s impossible to sue a large company but that is absolutely false, even for a few thousand dollars.
Now, if you are chasing people down pretty regularly, maybe you have a department dedicated to handling these cases and it makes sense. But if it's a once in a while occurrence, a few thousand dollars probably isn't worth the time and effort for an otherwise successful business owner.
I have a friend who worked for a large law firm and he told me that even they wrote off some unpaid bills or negotiated discounts. I was shocked to find that even when the lawyers could deal with the legal work themselves, they chose to pass.
That changed my thinking on the topic.
The reason was more to force their hand, but you don’t just “sue a large company” they will play games like ediscovery, and crazy-weird jurisdiction stuff