There can be many ways to see this one..
Everyone is correct in one way or another..
I think if this is the case with a het for albino, chances are, sad to say, it may have been intentional.
In a similar way, if dealing with a morph where the female is obviously more valuable, it may be the same case, and his lack of response proves it, to some degree.
In some cases where the animal is very low dollar, such as a $100 boa, i've offered as much as half off to keep the animal, since shipping back and forth again would make the total costs unreasonable, OR, i've offered to send the correct sex for half price and I would pay shipping.
This is of course if the seller and buyer are in agreements with this... if it's not too inconvenient for all.
Then there are times when this is not acceptable, and i've had no problems paying for shipping back, and sending the properly sexed replacement at no charge, shipping on me.
Taking care of business the right way can earn much more business in the future.
Trying nothing other than to save a few bucks almost always eliminates all hopes for future business.
Just my $.02
Hope all works out for you.
PS- There is always a possibility he can NOT contact you for whatever reason. I have payment from someone for nearly 2 weeks now and i've been desperately trying to contact them to ship their animals out! to no avail...
If I were to post this on the BOI, I would first start with an inquisition... 'Anyone know how I can contact so and so? I'd like to corrent a mistake... '
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Thanks and take care - Joe Rollo
'Tis not the stongest of the species that will eventually survive, nor the most intelligent, but the one most responsive to change' Charles Darwin