Advance deposit on property refund

if a person in 2013 -14 probably before rera act ... have bought property and paid some amount eg. more than 10 lakhs ... and builder was unable to complete the project after that ... and the person who paid the amount ... after years that is in 2020 is getting that amount refunded ... and the person was filling itr 1 earlier and now filing itr 4 .... what will be the impact .... and it's not sure that he will receive some interest on it or not ....