We can definitely provide you with some troubleshooting steps for this issue that you're experiencing with your new cell phone. Since the device is frozen and unresponsive, please try to Restart your iPhone Xs to resolve the problem. If that doesn't fix it, you can then follow the remaining steps listed at the previous link provided to perform a soft reset. If you're still having issues, the iPhone may be defective. No worries though, new Apple devices typically carry a warranty from Apple of 1 year after the purchase date. You can Learn about your options to replace a defective device here. Let us know if this helps.
Sean, AT&T Community Specialist
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