Debt Collection Dispute — client's check bounced after delivery

Quick background on my situation — any input appreciated.

client's check bounced after delivery. I've been dealing with this for about 15 weeks now and the situation isn't improving.

The amount being held/disputed is approximately $27,389. I have tried contacting customer support 9 times with no resolution.

Am I overthinking this or is this a real legal issue worth pursuing?

I've dealt with this before.

What worked for me was having everything documented. It took 3-6 months but was worth it.