I think you are bent upon insisting what you say.
You refuse to understand the legal position.
You know the original allottee has not got the property registered in his name.
He has to get it done - only then he will be in a position to sell it. Without registration, the original allottee is not the owner of the property. Therefore, if you want to get the property registered in your name, you have to approach only the first allottee and not the builder directly.
If you approach the original allottee, as already stated, he will not be able to register in your favour, as he himself has not got registry done in his favour so far.
In that situation, the original allottee if he approaches the builder, the builder will ask him to pay the VAT.
Similarly, instead of the original allottee, if you approach the builder direcly, (since you are approaching) he will ask you for VAT. Whether you pay or the first allottee pays the VAT - it is immaterial as far as the builder is concerned. All that he requires is payment of VAT.
Please appreciate. Possession is different and Registration is different.
Are you satisfied with the Possession. Then why are you asking for Registration?
Either persuade the original allottee to pay the VAT or you come forward and pay the VAT. If you do not want to pay VAT, then dont expect the builder to do the Registration in your favour.
THAT's ALL.