DELETE VARIANTS PROBLEM and PRICE SET to 0

Hio 2 more problems:
1- Some products display a price setup to 0 although no variant has been set to that price .
Ex: http://boutique.cbesprit.fr/store-2/products/selle-passager-royal-enfield-classic/

2- If I correct an attribute of a variant by creating a new variation and deleted the old one . Then the product box does not display the new variation and still proposes the old variation .
If selected , then the system will then issue an error saying that this variation is out of stock ...!
For ex: I created "Bordeaux" and deleted variant"Bordeau" . have a look here ... Bordeau is still available and try to select it http://boutique.cbesprit.fr/store-2/products/selle-passager-royal-enfield-classic/