alarm companies in dallas

I was told to send an email and the sevice would be canceled within 30 days. I did as I was instructed and sent the email and call to follw up where I was them and was informed I needed to pay a $1000 to cancel by customer service. I ask for customer loyalty and William told me I owe over $1500 to cancel
cause I had to buy out this ridiculous 5 year contract at over 60 a month, which I had only paid 3 years of, at the amount of over $2100. I feel this should be canceled in 30 days as I was told would happen with the first agent I spoke with through my app chat. The supervisor over customer loyalty said I could pay $800 and be good. As a company they are way more expensive than any other monitoring service
that can do exactly what they have done.