Service Tag & Express service code Invalid

I bought a M17x R3 on September 2011. The laptop is great! Dell support is very poor. I gave my the service tag and express service code to tech team but they can't find my information on the system. They asking me for order number but I didn't keep the receipt because i was thinking Dell is a big company I will have the support and help. I asked the tech team can I give my personal information that was asking when I purchasing the laptop, they said they wouldn't be able to find my information through that. Can someone help me please.

I'v had this happen to me..twice.

 What I did was ask for a supervisor in customer care. I had them look up my info and find the order number. I then switched over to tech support and asked for another supervisor. I gave them the order number and had him manually enter my ST and ESC into the system. It takes about a week for it to show up on their end. In the meantime the supervisor will tell a tech support agent to help you until it is in the system, they just can't order parts or send a tech to your house until it shows up.