Grand Carrera Calibre 36 stopped working

[*Aero*]

Hi, I had bought a rep Tag heuer Calibre 36 from one of our trusted dealers last March and it's been working fine until today... when I put it on this morn it was working ok but this afternoon I noticed it stopped. Tried winding it as I thought it ran out of steam but nothing, pulled out the crown, all hands move smoothly in all positions no hard points, the rotor at the back turns freely as well. I just dont know what happened

Any advice on what can be done? I think it will need a checkup at the watchsmith...