What is the point of serving notice???

I received an e-mail from Matrix to notify me that my upfront paid service was coming to an end. If I wish to cancel/terminate the service I should notify them immediately.<br> <br> I immediately responded, sent an e-mail to let them know that I sold the car therefore they MUST cancel my contract and should not bill me. I received two e-mails and I see that I am receiving two invoices. I check the first e-mail, okay, it is for the car that is with them. Then I check the second e-mail and I SEE THAT CLEARLY THERE IS NO POINT OF SERVING NOTICE. I wasted my time by sending you the e-mail.<br> <br> I sent an e-mail to debtors and I asked them to confirm. I even called and I was told that it takes some time to be off their books therefore I will be notified. WHAT A POOR SERVICE??<br> <br> Please correct this, I will not move to next door for your poor service. I want a stress free xmas too. mxm<br> <br>