Validity of property sale agreement, its cancellation and refund of advance

Respected advocates, I had entered into an agreement to buy a property and this agreement was NOT registered and it has a time essence clause of 3 months. I was unable to buy the property as I was unable to arrange the funds because of unforeseen family partition and issues, hence I notified the seller of the same and he orally told take some more time. After another 3 months I was sure that I will be unable to arrange the funds hence I requested for cancellation to which he agreed and we hand wrote the cancellation request and his acknowledgement on the same agreement where there was empty space at the end. And he orally told he will return my advance after he sells the property to which I agreed Recently seller has sold the property to a little lesser amount than I agreed and not clearly mentioning when would he pay my advance back. When I ask him he is saying he has suffered loss by paying EMIs and lesser sale amount so he has to decide on returning the advance Is his claim of loss legal? Is the unregistered agreement and its hand written cancellation valid? What legal remedies do I have to get my advance back? In Bangalore, Karnataka how long would it take?