Concert ticket row GA and GA3 whats the difference?

i purched 3 tickets from 2 different location online and both tickets
said that they would be
SETION: PIT
ROW: GA

but i got the first ticket in the mail and it says Section: Pit Row
GA3

so my question is.. is the pit devided into different sections? and if
so how do i go about getting them changed so all 3 of us can be in the
same section... seeing as that was what i was told i was purchasing. I
mean i paid 400 dollars for 4 tickets i should damn well get to sit
where i paid for.
oops i meant i paid 400 dollars for 3 tickets