my problem or AT&T's?

We are AS35985 and provide transit for AS36845. Currently, AS7018 is able to route to us (AS35985), but not our customer (AS36845). I have checked every looking glass and traceroute site I can think of. Every network I have tried has a route through us to AS36845 except AS7018. I of course checked AT&T's looking glass and didn't find a route to our customer. I would expect AT&T to have a route to our customer via AS1299, but they don't. Any thoughts? -Matt