Sometimes things just break, after just about two years its hard to access blame on the product or the installation…
I have never had to call CS for Thetford so don’t know how they are, but I would expect it isn’t unusual for many companies to turn down a claim on something almost a year out of warranty…
I am not familiar with the style II, and haven’t read a rash of complaints about them either… so I won’t rush to judgment about them…
My own experience, if my old one still worked fine, I would still be using it… almost all of my trailers that have had toilets in them have been Thetford Toilets (I think one Sea land) , and I have never replaced one yet or needed to… I have never had to replace even a seal yet, so for my money they must be doing something right, and doing it right for over 40 years now… before the RV toilets I had Thetford porta-potties at least 2 of them and I still have both of them…