If you are unsure of who your long distance provider is, or if you do not know if you have a long distance provider... perhaps you are afraid that you have been slammed (switched to a different carrier with out your knowledge or consent) then you just need to dial this toll free number and it will tell you what your current long distance provider is...
1-700-555-4141
EDIT - strangely, when tested with optimum voice so far all 1-700-555-xxxx numbers go to optimum voice directory assistance... further testing needs to be done... (the above number supposedly only works with land line carriers)
EDIT - when calling with a sprint (boost mobile) cell phone you get a recording "the number or code you have dialed..."
EDIT - when attempting to call from google voice it says "it appears that that number is not valid"
1-700-555-4141
EDIT - strangely, when tested with optimum voice so far all 1-700-555-xxxx numbers go to optimum voice directory assistance... further testing needs to be done... (the above number supposedly only works with land line carriers)
EDIT - when calling with a sprint (boost mobile) cell phone you get a recording "the number or code you have dialed..."
EDIT - when attempting to call from google voice it says "it appears that that number is not valid"
