[Resolved]  property — fraud

My Poa older is claiming to be a joint owner as she has done the registration on my behalf as per condition of the Poa. The sale aggreement has the Poa document attached at the back of the agrreement. She is clearly trying to extort money from me. Please advice. I have revoked the POA but wish to make my position safe. She has also had her name included on the share certificate of the flat.