1. Your father has already expired,
2. Put an application to mutate your name after recording your father's name in the 7/12 extract duly attaching the copy of the the registered sale deed, your father's death certificate and the legal heir certificate,
3. There is no law stating that if you delay in submitting application to mutate your name in the 7/12 extract, you will loose your ownership of the land,
4. Since your father has purchased the property through a registered sale deed from the owner of the land, it can not be sold by others and the subsequent sale deed is void at law,
5. File a declaratory suit praying for declaration that the property is inherited by you from your father who was it's absolute owner and also for a direction upon the Registrar to cancel the registration of the sale deed in favour of Solanki.