Zafira 07 plate loses power ?

Only had the car 3 months, over the weekend she stopped working all together wouldn't turn had her recovered they said battery so changed the battery plus put a new battery in the key fob , she started working, then today she lost all power the symbol with the car n spanner came on , as she was losing power on a busy bypass waited for her to be recovered the guy said it was bringing up fault codes for the cam shaft sensor an fuel system, while waiting for the truck she started no problems an was reving normal, where as before she couldn't Rev at all it was like she was staling . Now got her home took her around my village no problems an no lights on any ideas would be gratefully appreciated