I had a collection agency contact me once a long time ago. It was related to car insurance. I bought a different car and switched my insurance to the new car, and they increased my rates like 2X the price. I shopped around for quote right away, and easily found a place for like 1/2 the cost. I then contacted them to cancel my insurance.

Months later they sent me a huge bill, which I refused to pay because they dragged their feet canceling the insurance. Then I got a letter from a collection agency about it. I explained that I have been a loyal customer to the insurance company for X years, and always paid my bills on time. Explained that I bought a new car and they tried to rip me off, so I found a new insurance company for 1/2 the cost they wanted from me. That I had called them right away to cancel the plan with them. That I basically refused to pay their bill because they were trying to rip me off.

I never heard from the collection agency again. My credit rating has been excellent my whole life. I'm not saying you should do this, but just sharing my one experience with a collection agency.