My Samsung S5 is locked on Telus with SIM problems, could the sim be locked to Telus?

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AC Question

Samsung s5 locked on telus with SIM problems

I have a brand new out of the box galaxy s5 from telus and it worked for about 2 days then suddenly it would ask me for a sim unlock code, i decided to go back to using my old phone till i had a chance to take it in. well i figured i'd try to unlock it with one of those websites but they couldnt do it. so i put my sim card back into the S5 and then it didnt ask me for an unlock code but just said 'unregistered sim'. i rebooted it and now it just says 'emergency calls only' i have no clue what is going on.
also as a side note; if i insert an old bell SIM into the S5 it does ask me for my SIM network unlock PIN. so it must be locked to telus right?