Transfer & registration of property

I booked a flat in Noida (Jan'2012), at that time I was an Indian Citizen but living & working in Canada on permanent resident visa and in 2013 I got Canadian Citizenship. I got delayed possession of this flat in November'2016 and the builder asked me to sign a no dues affidavit so that they don't have to penalty on delayed possession. Since then I have followed-up several times with builder to register this flat but I haven't gotten a firm date from then as to when this can be done. Currently my flat is rented out but being a non-resident owner I am unable to properly manage it therefore I wanted to transfer this property to my mother and then she can register it under her name to do any further management of this property but the builder has flatly refused to do so even though I was ready to pay the transfer charges. As per Indian law is it legal for the builder to refuse transfer of property to the allottes parents? If not then what legal course of action do I have against the builder to persuade them to allow me to transfer this property to my mother and register under her name?