A few 50% off coupons appeared in my Amtrak account online, so I have been looking to take a short trip in the next few weeks.

However, the Amtrak website is really impossible to use:

1. There's no place to enter the coupon code when I'm booking a ticket. The coupons have a long string of numbers, and the blank where you can type in a discount only has space for 4 or 5 numbers or letters, so there's nowhere to enter them online.
2. On the app, I can type in the coupon code, as long as it is, but then there is a system error when I try to actually pay for the ticket.

What gives? I'll do anything to avoid a phone call, including taking a trip, so if it doesn't work online, I just won't buy the ticket.