Hi Norma56,
On two port systems your call volume may be high enough so that it may take 1/2 Hr. to light the message lamp. That's the lowest thing on the priority list for your voicemail to do. Call ext 78 and 79 to make sure they are both working.
To check the phone, Feature 09 <ext#> will turn the lamp on, Feature 10 <ext#> will turn it back off. MLS sets were bad for lights not working.
-Chris