sim card problems with lg motion 4g

[Android Question]

I have a galaxy admire from metro pcs. This guys sold me a lg motion 4g without a sim card. He told me to insert the sim card of my other phone since I have not disconnected it and he assured me it will work. I bought the phone without trying it. After the purchase I tried what he had told me and the phone just gets internet but i can't send text messages or phone calls. Does this mean the phone can't get service? Do i have to go to the store to change phones?

 

[Rukbat]

The phone could be SIM-locked, which means that it can only use a SIM card for the original carrier. (Phones can be unlocked,) Or it could be defective. Someone at the store should be able to tell you what's wrong. (At worst, if the phone works, you have to pay for an unlock code, which is a few dollars - look on eBay if it turns out that you need one.)