Please help! How to end contract with this property manger

[Lei Zhao]

Hi Friends,

I have a duplex in a not very good neighborhood at Forth Worth. The previous property manager sold his company to another property management team recently. During this transition, I have the tenant from one unit moved out. The new property manager seems nice from the beginning and communicate with me very actively to get the unit fixed and post for marketing. She asked for over $3000 for fixing several things in the unit, I sent money to her. I asked for the picture of the unit afterward, and she always had excuse she's not able to send picture somehow from her phone. A few days later she mentioned there're water leaking and mentioned she has the video of the damage. I asked her to send me the video. She said she can't send video from her new phone for no reason. After I sent the $3000 she's like a different person. I sent email to check update on tenant, she doesn't reply. I really think I'm in a bad situation. I'd like to end the contract with them asap, and even thinking to sell this duplex. Please advice how should I proceed on ending the management contract with them in this situation since they can put faked bills of thousands of dollars on my account and charge me for that when we end the contract. 

Thanks

Lei