My y625 hasn't any service.

Hi,

If you've tried a different known working, network compatible SIM card and it still doesn't work properly and since it is new take it back to where you got it from and get it replaced under warranty.

If the retailer doesn't want to know about it, consult the manufacturer's warranty statement that should be with the documentation that came with the phone, as to what you have to do to make a claim for a manufacturer's warranty repair, replacement or refund. (if it not a separate document, look in the User Guide, if you have none, search for Huawei Y625 warranty for your location online)