Called SiriusXM US for a better offer on a second radio

[jcol]

I created an online account with SiriusXM US a few weeks ago and am paying pretty much full price for one radio. I have a second XM radio that I'd like to add to my account and this time I thought I would call in and see if I could get a better deal then the $9.99 per month listed on the website. I first tried to call last evening and waited 20 minutes before I gave up so I tried again first think this morning. This time it was a 10 minute wait but I did finally get to speak with a customer support person. I was unable to get anything other then what is on the website for a second radio. I believe the person I was speaking with was from a call center outside of the US. Can anyone suggest a better time to call and who I need to talk to? I have seen numerous posts about people getting better deals but perhaps those deals are offered when people threaten to cancel the service?? I have also seen some promo codes but I don't recall seeing a place to use these codes on the website so I assume you still have to speak with a CSR to use them?? Any advice would be appreciated.