There are some models of SPA devices that were sold directly to providers and came pre-provisioned. These devices cannot be reset to factory defaults or reconfigured. Do you happen to have the exact model number of the phone from the sticker on the bottom? Usually if there is something like -rc or -sf after the model number it means you have a pre-provisioned phone.
You can also give us a call at the SBSC and we can look up the serial number for you to check if it is one of those phones or assist in attempting to reset it.
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