Serving a notice is a ****!!

I wanted to cancel my medical aid, so I called Bonitas and I was advised that I needed to serve a 1month notice to avoid having outstanding debts. I did that and to my surprise after serving that notice I got a letter saying I still owe R2451 so I thought to myself I should have just terminated the scheme with immediate effect and paid whatever that was outstanding and it would have been less than paying R5551 and the R2451.. So dont serve the notice just pay whatever amount they say it's outstanding.