Just another spin of the old broken record: be careful about "going all-electronic." This is a perfect example of something that is more likely to happen with an all-electronic system than a mailed-paper-based system.
It's particularly bad if the billing only happens once a year. And people forget that simply renewing a credit card--no account number change, just expiry change--is a credit card change and all your accounts that bill the card need to be updated. You do, of course, have a list of every online account that has your credit card information? Really? You actually do? Well, I'm impressed, because I sure don't.
A problem that people are unaware of is--this is based on personal experience, not statistics, but I'll bet the statistics would bear me out--people gripe about the USPS, but paper mail delivery is far more reliable than email delivery. It's not that unusual for email to be lost. Worse yet, because people sometimes get notified of an email delivery failure, people assume that they will always get notified; 'taint so.
Anything that's from a company, even a completely legitimate company that you've done business with for years, can trip a false positive and fall into a spam trap, and the companies that operate spam filters are always tinkering with them so a notice might get through last month and next month, but not this month. I used to think the answer was letting you see the filtered messages, but I now have a couple of email accounts that do let you browse the "quarantine" area, and it's no good: I can't summon the energy to read a hundred subject lines every week about Viagra, and about Mrs. Anne Gomes (who is suffering from a cancerous ailment with limited days to live and wishes to donate USD 3,300,000 to me because she trusts me to carry out her wishes to uplift the downtrodden), looking for real messages which are never there, except when they are.
Annual income twenty pounds, annual expenditure nineteen nineteen and six, result happiness; Annual income twenty pounds, annual expenditure twenty pounds ought and six, result misery.