Guardian Protection

I purchased a brand new townhome in June and selected Guardian Protection to be my security system provider (which was definitely a mistake). During this time I signed a three-year agreement for services, and within my contract it states a $750 early termination fee to cancel the contract. I sold my home on March 30 and moved into an apartment. The new owners of my previous home expressed interest in taking the service over, to which Guardian explained to me that was possible and would relieve me from the early termination fee of $750. The new owner contacted me on Tuesday, May 9 to let me know that apparently he and his wife could not start service until my account was disabled. I promptly called Guardian's loyalty department the same day, letting them know again that I sold my home and that the new owners would set service up once mine was cancelled. We cancelled my account over the phone and I signed a discontinuation or something like that. On August 24 I paid Guardian $161.97. Prior to that, my last payment was February 25 and I was still one month behind. With the August payment, I would technically have been covered through April. In September, I kept getting calls from Guardian asking about installation. I was confused. I told the man no and that I moved to an apartment and mentioned the new owners taking over. He told me they never did, to my surprise, so I asked for them to bill me for the early termination fee. I get a document from them saying I have to pay $1003. Of course I am not going to sign off on that. My contract that I signed in the beginning says I am liable for a $750 ETF fee only. I am not paying monitoring fees for a home I am not living in anymore, nor is the system still active. I cancelled everything in May, and they continue adding money as if they are owed that. I truly regret signing up for Guardian and not Vivint, and to think I recommended Guardian to both my sister and brother. Luckily, they ghosted my sister so she went with ADT instead.