Dell PC TuneUp Renewal and Upgrade Failed

I renewed my Dell PC Tune Up subscription yesterday (have used it for 3 years), and the new Dell PC TuneUp upgrade installation froze and failed to  install properly. I was required to uninstall  System Mechanic to re-install PC Tune Up. Now, whe I download and try to re-install, the installer does not recognize my new activation key.

Try as I may, I cannot find any Dell Technical Support contact to help me solve this problem. Does anyone have a suggestion?

Thanks in advance...