1. There is about 8V at the charging pins (not pin's) of the base
unit.

grin

I have googled a ton of websites and one of them mention that
this voltage at the base unit should be varying from 4V to 8V and when
the handset is placed with battery connected, it should drop and
stabilize at about 3.6v. In my case, the voltage is fixed at about
8V and does not vary.

Hmmm... Interesting.

If the battery is pulling current, then the voltage should drop. That it
does not suggests that (QED) the battery is not connected. Have you checked
all the wiring in the handset, to be certain the battery is properly
connected?