Central Security Group Threatening tone when attempts to cancel. Attempted to extort money for services not received. Tulsa, Oklahoma

When my credit card for my account with them expired, I decided not to renew my contract which I had had for 13 years - so any of their hardware had been paid for many times over.  The original contract was about 3 yrs.  When I cancelled by phone, they continues to dun me with bills.  When I called again, she  found that I had called and cancelled in my file , but "Oh you have to write to us".  I wrote, I emailed.  Still the bills came.

Finally,  I received a call from a woman who said that I could not cancel without paying for a year's worth of service which would be end in September of 2015.  This made no sense to me.  Then she said that if I found someone else to take over my account, they would waive those charges.  I told her to get a lawyer, that I was not paying.

They also told me in all three calls that I would then have no fire alarms  I checked ith my local fire department and found that also not true.

These people  play hard ball.  I would not deal with them again.