Tow company sent me to collections for car I sold years ago (have bill of sale) but didn't properly notify the DMV on time. Do I have any legal defense? If yes, what are next steps.

Location: Oregon.

I sold a car about 2 years ago to a salesman at a reputable dealership, but important to note that I sold it to the individual man personally. Not the dealership. I was leasing a new car, needed to get rid of the old one and his family member needed one so he said he would buy it off me. All of this happened on dealership grounds though during his working hours so I thought it was a trustworthy deal because why would you pull something shady on the company's grounds. I couldn't find the title but the car was old enough that it's able to be legally sold without one, but still he printed a replacement title form, had me sign it and told me he'd take it to the DMV and if he had any trouble and needed me to come with him he'd call. Otherwise he printed out the bill of sale, put it altogether with my new lease paperwork in an envelope and said I was all squared away.

I never sold a car before and like I said I thought he would not steer me wrong because again super reputable dealership (associated with one of the big corporations, not a local used one) so I was like okay cool done. I didn't realize that I needed to file a notice to the DMV because he told me after all the paperwork I didn't need to do anything else. So now it's two years later and I got a bill from a towing company and they have now sent me to collections because he never got a new title, registered the car, anything, so it's still linked to me at the DMV. I called the guy and he still works there and told me to submit a notice of sale but obviously the tow company doesn't care because it would have needed to be submitted before the towing. The guy said in texts that he was willing to go to the DMV or even go pay the bill but then of course that was a lot of talk and he ended up being like 'gee I don't know how else to help, the towing company said they wouldn't accept my payment unless you have the title so I guess you'll have to go to court.' .. which I highly doubt the tow company cares about seeing a title so long as the bill gets paid but whatever. Either way the guy is not going to help. And supposedly he says he sold it to someone after that too because it was totaled but at this point who knows what he's bullshitting me on. Lesson learned.

So I've called the collections company, explained I have the bill of sale, the sale notice (that I filed too recently for it to matter), and text messages from the guy that clearly indicate he bought the car from me and I'll send all that in. Of course they reiterated the notice of sale would need to be dated properly so this isn't going to go anywhere but bought me time I guess since they're waiting on all of that paperwork to review. So with that background done- what exactly do I do now? Do I still send in the paperwork even though they've said they don't care. If I do and they again state it's my problem, my bill, do I wait for them to sue me and get a lawyer? Additionally if I do wait do you think this is sufficient evidence to prove that I sold the car or do you think I'm screwed because I didn't notify the DMV of sale on time and I should just suck it up and pay the bill now before it gets worse? Like do I have any chance of winning this if it goes to court?