Home phone voice mail access number

[mikefx]

I am trying to access my home phone voicemail (area code 508) from England. The access number is {edited for privacy}, which the Verizon site has just confirmed is the correct number.

But whenever I try to call the number by an unusual method, the call does not go through. By 'unusual method' I mean a Skype call or an English discount dial service.

Is the Verizon voice mail system working? Is {edited for privacy} still the correct access number for central Mass? If both those are 'yes', then does remote mail retrieval work when called by one of these unusual methods?

Thanks