Amendments to a variable product

A clients site >> [login to view URL] has a j2store plug-in. We have created a variable product online > [login to view URL]:multi-buy-lg-4w-led-gu10-warm-white-packs-of-3-bulbs However, when you select from the menu > Shop by base > LED GU10 ([login to view URL]) it gives you an option to add to cart - yet it lets you select 8 packs for the same as 1 !!! Obviously not ideal and client has had to honour these orders. Need it fixed - fast - help!