After re-install mcafee, how to restore subscription?

I recently purchase a new DELL pc, and the package included 15 months of subscription of McAfee anti-virus. Without aware of activation, I reformatted my new DELL PC without activate the McAfee. Now I reinstall the McAfee anti-virus software from the CD that come with the system, it only give me 30 days trial.

 

How am I getting back my 15 months subscription to McAfee anti-virus? Who should I contact regarding this? been tried to contact McAfee, no response. Trying to email DELL, website error.

 

Thanks in advance for any good advice.