Offer to purchase house

I sign an offer to purchase a home for R 860 000, Now that the bond is registered and the money is due to pay out, I find that the document was amended and now I have to pay R 20 000 more for the house.<br> <br> According to the attorney I don't have case and I will lose the money.<br> <br> Feel that the agent knew that the document was filled in incorrect and changed it afterwards and did not tell me because that will affect his commission.<br> <br> Adriaan Smith is not trustworthy and a *****!