My client who is a sweet food store owner but not the property owner terminated our remodeling contract on Nov. 19, 2019 without any warning or discussion. I mailed the preliminary notice to the property owner on Nov. 25, 2019 in order to cover the service payment between Nov. 5, 2019 and Nov. 19, 2019. I stopped working on the project after I got the notice. I requested the service payment through phone call and text message. The client never responded it. Then I emailed her the bill of $9500 and also indicated interest rate, collection or mechanics lien could happen. Her lawyer sent me a letter and said I made threats to the client, the threats are tantamount to extortion and warrant exploration of all legal and nonlegal remedies against me and my company as well as listed other wrong actions which I made. I have been feeling very unfair. I only need a dialogue and I am willing to re-think the payment the client should make. What should I do for next step?