Thank you Solaire for your suggestions. Just today (I have been working on this issue for four days), I tried changing my password, repairing the app ("app recovery"), and logging in and out of the app. One of those things must have worked. I am no longer getting the error and was able to move forward with my purchase.
Honestly, I am considering no longer making large EA game purchases through EA in the future. I could always use a different provider for future or consider different games. It is disappointing though as I have been an EA customer since the first Sims came out. Probably more than 20 years ago.
If they do provide customer support directly and in real time, in addition to this resource, that is great and essential for me as a customer; however, access to it is not easily identifiable from the website. That is disappointing and overly time consuming for any customer.
I have not tried what you suggested in order to access customer support, since the website options led me away selecting that option. But all other options that seemed applicable to my situation, such as getting help with a purchase (as this was the problem I was having) were dead ends when it came to reaching customer support. I could not even email EA Support as the email came back with a note that email support was no longer offered. I don't think most new customers would have tried so hard or should have to get access to a product.
There is no easy way to reach tech support that I have found in the last four days, in which I have been working on this issue and been trying to make my purchase. If that is not, so I hope EA will take this message in account as feedback to make their live support easer to find and access.