With this answer I think they are more of the repayment idea than asking developer to continu it; they probably don't have any more information than us so I don't believe their answer changes anything.
I don't blame the developer, sometimes things does not take place as desired, you lost envy, the amount of work is higher that you though... And the feeling to be forced is one of the worst thing for an artist.
Didn't he 'offered' this to the ones who bought previous abandoned project ? I don't think he has malicious attents (perhaps he should just consider avoiding selling uncompleted projects).
Atleast me I don't feel scammed, the generator is already strong and I found what I was searching first (even if I have more work than expected to do on it); I still hope that this project will be continuing, but if the developer could just clarify the project situation (and potentially share some work done but not included yet in this version), I would be happy =)