I work retention, too, just for a different field. I start by assuring them I'm going to take care of them. Then start a discovery phase where you get as much info as you can from them using mainly open ended questions. Maybe along the lines of "What are you going to do without these security features?". "If price wasn't an issue what security features would matter most to your family?" "How many people drive the car?". Etc.

Thank them for the information, then use the info they just gave you to re-sell them on the value of your product and how it applies to them. Maybe like "You mentioned your daughter is using the car on the weekends... Blah blah blah features that make keeping the service a good idea.". Go for the close here, upselling any ancillary services that fill a need you uncovered during your questions.

Maybe they'll take the deal, maybe not. Keep your head out of your customer's pocket. If they still want to cancel then put them on a brief hold while you calculate the discounted rate you're going to offer them. Come back and offer the discounted service.

Be careful not to offer even steeper discounts if they reject the 2nd offer without altering the plan somehow. Movement generates satisfaction in negotiations. If you have a minimalist security option with super low prices go for that as a 3rd offer just to keep the line of business open. Then go ahead and cancel the account. It's retention, you can't win them all. Just try your best to keep a positive attitude, and always attempt a save on every account