Before I signed an Option to Purchase to buy a Housing Board (HDB) resale flat, I was told that the seller was migrating to Australia. Later, I found out that he was selling the HDB flat because he was hounded by loan sharks. I stopped my cheque immediately because of the "loan sharks" issue. I want to nullify the purchase on the ground that the seller had "deceived" me about the reason he was selling the flat. Can I nullify the purchase?