Did they sell you on a harness adapter ?
Bestkits.com say'*: "Must Relocate Factory Radio"
You probably need this part instead.
Peripheral Electronics Add-A-Heads
My guess is either someone didn't wire something properly or that the wires in the factory harness don't match up properly with the harness adapter that they sold you.
This has happened to me before and I have had to pop out the pins and reconfigure the harness adapters and the peripheral add on'* to get things to work properly.
Take it back to where you had it done and show them whats happening.
92 Bonneville SSEi - Stock - Remaining repairs needed due to neglect by previous owner - ABS/Trac, AC.
Mods so far: Maganflow High flow Cat, Rebuilt */C
Future Mods: Interior swap for Leath, High Output Altenator, Crazy system, Climate Control swap & Custom Exhaust/Intake.
98 Dodge Stratus - Wifes Daily Driver
92 Dodge Shadow - My Winter Beater