I used turbotax.intuit.com/go/amex to get the $15 discount and now I realize that the $15 was never applied. How do I contact you to discuss this issue?

[mesquitebean]

Normally when you use a partner discount portal, one would need to go there each time and file from the discounted site.   That's how it knows to apply the discount.

See this FAQ:
https://ttlc.intuit.com/questions/2824053-how-do-i-get-my-turbotax-affiliate-partner-discount

Here's how to discuss it with TurboTax Support, but as the FAQ above indicates, they may not be able to do anything after filing.

FAQ:  What is the TurboTax phone number?

https://ttlc.intuit.com/replies/3300041