Dear Sir/Madam, its all depend upon terms and conditions of the sale agreement/absolute sale deed/MOU between the purchaser and seller. If you have found as per your query in the above said documents you have every right to get compensation for the delay in the form of deficiency of service by way of filing petition before the district consumer forum, before going to file the petition, you should issued a legal notice to the said builder/promoter in respect of the same for your claim... if you want my legal service I will do it.
This is a common issues many buyers are facing with the builders/real estate companies/realtor. Yes, you do have a good case. You can file a consumer complaint. Ensure you have all the papers in place required for proving your case.