I would suggest writing to them via their email. It will take a bit longer, but I've found it to be effective.

In my case, I've had their Visa for a while, and recently switched to the MasterCard. Technically, I'm not a new customer, and not officially entitled to any miles since it's not a new account. I wrote and said that I'd heard of their bonus offers. While I don't technically qualify, I use the card this much each year, blah, blah, blah. Just got 10K miles from them for being a good customer.

It all started with an email, though, so I have faith in that approach with them.

Cheers.