More often than not we can resolve the payment issue without any customer involvement. That's the ideal path. In many cases the system will delay sending communications if the chances of a recovery by retry drop below a certain level. It's best to avoid asking customers to do something if it may already be fixed. Your bank still may notify you but that depends on your country and bank.

We don't guess a customer's language. Typically our Merchants have a single default language but since our Merchants are global it's important that the various messages we send can be available in different languages. If they have multiple instances for different geo's we can segment by language.

Our transactional emails have incredible deliverability scores and extremely low spam rates. They come from the merchants domain and are lightweight to ensure they go to the right inbox vs. ending up in promotion. For transactional sms we handle the compliance and each Merchant get's their own dedicated #.

Regarding pricing, each Merchant has different volume, failure rates, and recovery rates. Since we guarantee our ROI we have to tailor our pricing to them. We're working to make it easier so this is helpful feedback.