It's like Mercedes trying to charge a monthly subscription fee for heated seats. When you do something like this to consumers, you lose their trust and you will never gain it back.
AFAIK they offered monthly, yearly, and "unlimited" subscription. In that case what's the issue? Heated seats are frequently an upgrade option. What's the problem with offering payments as an option?
Or rather than imagination, simply draw on experience with other companies and ither subscription models.