When I put the SIM in, the phone says INVALID SIM; INSERT THE CORRECT SIM; PHONE LOCKED?
What is your phone brand and model?
If your phone says displays invalid sim error or sim not valid,sure it is locked to network.So you need to remove the phone from current network lock.Then only you can use with other network sim card.You can get the Unlock code from the site Prounlocking.com and unlock it from service provider lock.But you need to find the current network and country it is locked now.Then check whether unlocking service is available for your network,country and buy the service if its available and unlock your phone safely.If your phone is an iphone get remote unlock service from there itself and unlock it safely.
