Bearing in mind string tension, I have to ask whether you are buying from an authorised Yonex dealer. Something is very wrong for three racquets to break at 12 o’clock position within 3 weeks of use. This is the most unlikely position for a racquet to break and makes me very nervous about the racquets or stringer.
 
If the racquets have been strung at this tension and have not been involved in collisions, then I would return them to the place purchased and ask for them to be sent to Yonex.
 
Quality control at Yonex is very high. These top of the line racquets are manufactured in Japan in almost laboratory conditions. They do not have B stock as they are destroyed so only the correct specification leave the factory.
 
Racquets normally break at 10’clock or 2 o’clock positions so it makes me very wary that they are genuine.
 
Paul

That’s good news – well done.
 
Sadly, although Yonex is an international company, they do not have an international warranty. Therefore racquets purchased outside the country of residence will not be covered.
 
If it proves your stringer it at fault I hope they pay for the VT80.
 
Paul