Why companies lose hundreds of thousands of dollars in Subscriptions?

Getting Subscription Management and recurring payments right is hard.
Companies learn the hard way that custom solutions are painful and a liability.
That simple Stripe solution becomes a bottleneck and a nightmare to maintain when scaling.

I've seen companies lose hundreds of thousands of dollars because of this. These are some of our team experiences:

• Payments being charged twice
• Payments failed with no reason on background jobs
• Magic payment cronjobs stop working and no money was charged for a couple of days.
• Unable to process payments in checkout from customers that are located in different locations from their legal or card address.
• Expired coupons applying on subscriptions
• Coupons applying on up/down grading plans which weren't avaliable for that coupon.
• Wrong global tax calculation in invoices and therefore on payments.
• Complex Usage based pricing being wrong charged in plan.
• Addons being charged more times than it was supposed or being duplicated.

Surely, many of you out there have experience this or other issues and can share your experience?

Note: I am Co-founder of Abowire and eagerly working to avoid subscriptions businesses go through this pain.