Hero Electric — Bill not provieded & no registration even after charge

I am Shivanand Neji from Bhadgaon Taluka Gadhinglaj Dist kolhapur Maharashtra (Mobile number [protected]).
I have Purchased 2 vehicles
1. Optima Hx and
2. Flash 10 months before From Sub dealer Tushar Patil, at-post Nesari, taluka Gadhinglaj, District Kolhapur, Maharashtra and main Dealer Ambika Motors, Gadhinglaj, Kolhapur Maharashtra. RTO Registration has been completed completed for Optima Hx but for Flash registration is still pending . even after they charged for the same. We are continuously asking for the bill they have yet not provided us the Original Bill. Now they are denying payment received and vehicle sale. We have both vehicles with us at our location. They are not providing us proper services too. So what action should be taken against this issue?
please look into the matter and do the needful. awaiting for your reply.
Thanks and regards