If an outbound call to a toll-free number is rejected, typically the problem is that a toll-free number will reject a call based on caller-ID. If the caller-ID is either "unknown," mal-formed, or another toll-free number, many toll-free recipients will reject the call. They may, sometimes, reject a call by area-code. If they have a local number in that area code, they will reject calls from that area code forcing local dialers to use the local number, for which they pay a lower rate.
If there is a number that you call often that does not accept your caller-ID, setup a new user with a different caller-ID. Setup a second line on your phone to use that user for outbound calls to that phone number. Multiple users could share that same username for outbound calls. It is not necessary that you create a new account for each user just for this purpose.