Were you just extremely unlucky, or doesn't your bank account number have a proper checksum builtin to prevent this?
Also, in my native Belgium, bank payments have had automated payment processing structured messages attached to almost all {b,c}2b payments. That one contains a similar mod97 check.
[0] https://en.wikipedia.org/wiki/International_Bank_Account_Num...
And if numbers are getting keyed in tens of thousands of times per day across a large business, and mistakes happen hundreds of times a week, a checksum that catches 95% of errors will still let tens of errors go undetected every week.
What annoys me is that these are both problems with technical (mostly) solutions. The big banks don’t have magic humans that don’t make mistakes, they just have better systems that reduce error, and can fund development of better apps.
I personally use only the web client of my bank, and am very happy with it, but will admit that the mobile banking app is less than desirable. Wish they would all just make PWAs and call it a day.
Also one time the credit union let someone sign my account up to pay for their car loan, because the clerk who set up the automatic payments accidentally typed in my account number, which was one off from the car loan holder’s. To their credit, the credit union was quick to resolve the issue, but it left a bad taste in my mouth that it was so easy for them to make that mistake and nothing on the back end to catch it.