It is mind boggling to me how many websites make it difficult or impossible to express the idea you no longer wish to use an old credit card
Sigh. My career was in logical and enterprise data/information modeling. This was the kind of thing we constantly bumped into.
It takes a fair amount of time to learn about/appreciate the vast quantities of use cases and gotyas one needs to model for. Also for folks to really understand that logical and physical models are different and necessary. The stories I could tell...
Squeezing that into one week? I salute your effort!