How to distinguish the gender of Rainbow Jackson and Veiled Chameleon?
 

I recently purchased a Rainbow Jackson Pair and Veiled Chameleon male from the Underground Reptile Online Shop.
But I have problems with their gender.

First I bought a Rainbow Jackson pair, but I think that I got two males.
I know that Rainbow Jackson's females also have horns, but I know it has a very short.
But they're perfectly the same color, and both have pretty long, straight horns.
The large chameleon what they said to be male is 9 inches long, and the length of the horn is 3/4 inches.
what they said to be female, are as small as 7 inches long and have horns about 1/2 inch.
The reason I think they are all males, they both have a small lump at the base of their tail.

And also, i bought the male Veiled Chameleon either.
But.. it looks like female to me.
they said it is male.
but i can't find a any bumps on the backs of his(?) hind legs.
funniest thing is they said "There was no sex chosen for the 12+ inch veiled"
look at this link.

https://undergroundreptiles.com/shop...led-chameleon/

Regardless of whether there is a choice or not, it is already marked as male there with photos too.
it's a all about the male.
after then now they are telling me they sent me a male.
I don't know what's going on right now.
The chameleons arrived with signs of severe dehydration with sunken in eyes.
They haven't been drinking water properly for at least a week.

I need your advice, please help.
Are they really a pair and males?

Tell me anytime if you need more photos

I agree, the Jacksons both appear to be male. Although the female jacksonii jacksonii can have three horns, the horns are typically very diminished compared to males, their body shape is different and their typical color/pattern is different from ales. Looks like you got a mature male and a younger male.

The calyptratus looks like a female. I checked the link you sent, the description does indicate males. Even if you're given an option to select the gender, I would have expected to get a male unless I specifically selected female.

Hopefully UG reptiles will make it right.