Yes, your website will absolutely keep working if you stop service. Your website is yours, and you are always free to take it where you like. Billing for the care plan is month-to-month.
You own your website. Most of my clients have been with me for years, but it’s not because I have long contracts!
Since my support includes web hosting, which is how your site is made available on the internet, if you stopped service you would need to find another web host and pay them a fee to host your website. Usually, they will migrate your site for free in order to get your business. I can wrap up your site in a migration-friendly package and send it along to you, and you can arrange to have them take it from there.
If your site uses premium plugins (see question # 2 above), your site will keep working– however, you’ll need to purchase the licenses to use the premium plugins on your own and keep the license(s) up to date. If you don’t, you won’t be able to update those plugins, which can lead to security issues like a hacked site.