1) Builder cannot ask the customer to pay him the market prices and as such the demand of extra 10 lakhs from the builder is grossly illegal and against law.
2) In your case, you should issue legal notice to the builder on the following lines
a) That the builder has delayed the construction and
b) That he has not come forward for registration of property in your name and hand over possession of property despite the project being delayed by over 14 months and
c) That his demand for Rs10Lakhs over and above the agreed sale consideration is grossly illegal and
d) That in the event of builder not completing his part of contract(i.e handing over of possession and coming forward for registration) within next 30 days, you will pursue legal action against him.
3) In your case, in all probability, the builder must not have registered under RERA.
4) You are at liberty to approach the consumer forum or civil court for relief(issue directions to builder to come forward for registration and hand over possession).
5) Under consumer laws, the builder is liable to pay you interest for your advance monies that are lying with him or alternatively pay you costs of alternative housing.
6) Adequate care should be taken by you to ensure that the builder obtains a No objection certificate from Tata Capital , prior to the registration of property in your favour.
Hope this Information is useful.