Dan,
After reading your post, it appears that the dtmf from pressing 3, or 8, or 9, # on the phone are not being recognised from your service provider. Please check if the service provider supports inband or out of band DTMF and the method they support.
The phones default DTMF Tx Method is Auto
Login to phone admin/advanced and go to EXt 1 page
Audio settings -> DTMF Tx Method:
The options available are:
InBand <--try setting this option
AVT
Info
Auto
InBand+INFO
AVT+INFO
Regards,
Randy