Rebate

I ordered comcast digital cable service from Broadandoffers.com. I can get $150 rebate for modem and other services. The company asked to send in the rebate application in 2 months. but it also asked to attach first month bill from comcast. I forgot to send the aplication on time. Three months later I sent out the application forms. I checked the status of these rebate and found thry were rejected for overtime.
I called the rebate company. They told me to comtact dthe Broadandoffers company. I called the Broadandoffers caompany. i was told I can not get the money since it is my fault.
What can I do then to get my rebate back?