Can a landscaping co. file a home lien and a report with the credit reporting agencies over a disputed bill without a contract or agreed fee schedule?

My old landscaping company sold out to a new company last summer. There was never a signed contract or agreed upon fee schedule. I was unhappy with the service this summer and terminated them. The final bill for mulching and edging beds came in after the termination and was excessive and well beyond what the usual fees had been. This was clearly a retaliatory tactic. The bill was for 2,300. I sent a check for 600 which was cashed and offered to pay another 600 if they would send a final invoice reflecting that this would be payment in full. They responded by demanding full payment and threatening to place a lien on my home and report me to the 3 credit reporting agencies. Can they do this? There was no contract and no agreed upon fee schedule. Their charges are excessive and arbitrary and I did not agree to them in advance. I don't want to pay but also don't want a lien on my home or a fight with the credit agencies. Please advise. I am prepared to meet and hire an attorney.