Recently signed up for this card and spent what I thought was >$3000. I sent a secure message and asked the rep to confirm I met the requirement a few days before the 90 days was up. They replied and said I did meet the spend requirement, and should receive the bonus. 8 weeks later no bonus. Messaged them via secure message (and called them), and was now told I didn't meet the bonus (was short by a few dollars) despite being told earlier that I did, and there is nothing they can do.

Is there any way I can escalate this further and get a favorable resolution? Write a letter or contact someone more senior through another channel?