Buyer able to place order at much lower rate - on my gig !?

[selinavoiceover]

After the original order has been placed, how is it that voice over clients are able to purchase an add-on, -at a price much lower than what I usually charge (10 USD per 50 words?!!) ? And HOW can I change that setting ??? I've combed through all the pricing details for that gig, at NO POINT, am I offering this pricing.