nflorentin mentioned the probability for this occurring. Either take out the 20 number to something much higher or use new Date().valueOf()

Ah, so a SaaS site where users can enter their Stripe API KEY and receive payments through your application. Funny, I'm actually working on one of these right now so I'll be sure to take notes of certain aspects during the process for this episode.

I would likely handle it very similar with a Vue controller. The actions on the objects would be slightly modified, but more or less very similar.

See if something like this will work.

customer = current_user.stripe_customer
subscription = customer.subscriptions.retrieve(current_user.stripe_subscription_id)
subscription.cancel_at_period_end = true
subscription.save

It looks like you're not getting the stripe token passed in from the form. In the form where the credit card is entered, the stripeToken should be added in via the javascript. Make sure you don't have any JS errors. You could try to comment out the form submission so that you can inspect the parameters that it adds in. If its not adding those in properly, that could be why you're getting the errors on the controller.