I have bought an office from the honour and get the affidavit of it on my name and submitted to the muncipal authority to transfer it to my name, but

Sir, I have bought an office from the honour and get the affidavit of it on my name and submitted to the muncipal authority to transfer it to my name, but unfortunately complete file was missplaced. During this time I sell this office to another person but I ask the first honour to give affidavit to buyer. Unfortnately the buyer is not giving me any response about my payment and he just want to transfer this office to his name in free. Please give me some legal advice about it how can I cancel his affidavit as still office is not on my name. Give us suitable answer of it.