| | Re: 9550 sim problems
The 9550 is a "world phone". It has CDMA bands as the primary bands and secondarily GSM bands.
Typically, CDMA carriers only allow devices branded to their network to be activated on their network.
Note that the CDMA side of the device does not use SIM cards, so it does sound like the representative was correct. The device may not have the proper HSPA bands for the MTS network. So you may not be able to activate it with them with a SIM card.