Reward Cards stolen in transit, AT&T says they are not liable!

I had 2 reward cards, $200 & $100, coming our way for signing up for U-verse for a year.  I and my family were out of the country for 20 days. Once we are back and inquired about Reward Card to Reward Center and Service Center. We were informed Cards was mailed/activated and used when we are out of the country. Since Reward card was mailed incorrect address they said were not liable and didn’t try to help with this.

What I find odd is that the only reward cards that have disappeared in the mail are ATT cards. I have received other rewards cards safely in the same mailbox during the same time period!

Let me know if anyone can help me with this!