Why can't I talk to someone about reward card?

Rewards phone number 800 288 9983 does not work. Nobody picks up.

I was told I'd get a $400 reward card. My account online says eligible for $50.

Chat doesn't work, regular customer service doesn't work. They all say need to contact rewards. Well, I did, and I can't get through. I'm not wasting time trying to figure this out. $400 is like 4 months of service, its a big discount, and a major reasoned I signed up for the service. I want someone to address this ASAP.