Customer care unable to detect express service code

Hi,

When ever i call customer support with the following number 18004250088 and while it is asking to enter express service tag and when i enter it says "unable to find service code"

Kindly please help me to contact dell customer care.

And also when i plugin the charger to the socket i get vibrations kind of thing as my laptop is having metal cover.

kindly help me please or/else please let me know official dell support center in Chennai

Thanks,

Tabrez