What happens to my Bars if I cancel?
When your subscription ends, the Bars you bought are kept, but can't be spent until you subscribe again; your monthly Bars expire at the end of the month, as they always do. Bought Bars are never forfeited: subscribe again and they are spendable at once, in the usual order after your new monthly Bars.
The same applies whether you cancelled or a payment failed and wasn't resolved. If you close your account instead, the Bars you bought and haven't used are refunded, at $1.00 per Bar with the sales tax you paid on them in proportion. While the subscription is ended, the account uses the free tier.
See also: How do I cancel my subscription? · Can I get a refund?