Marshall White Paint Fiasco

I bought some Marshall pure white paint. The area to be painted was a light color, almost white. The paint was put on three times. Every time it dried, it created a wavy look. When I say 'wavy,' I'm not talking about brush strokes; it's like another color seeping through, forming a wavy pattern in droplet shapes. When we complained to the seller, they told us that Marshall's paints might be defective. Are we going to end up having to purchase this item twice if it turns out to be defective, like a child's toy? This didn't turn out well. We're hoping Marshall will address and fix the problem, but we're not too optimistic.