G2A help!

Keep in mind that they can randomly start to say it is not enough and demand your proof of purchase in PDF format, your social security number, shoe size, bank card number, list of current clothing, permanent address, and the telephone number of the neighbour's barely legal daughter, because
a) they can be dicks if they want to
b) they are a bunch or really bored office workers employed by two people not exactly known for their generous waging, sitting in either a Polish or a Hong Kongese office that neither strike you with much confidence looking at them on Street View
c) they can be dicks if they want to
d) they can harass you enough so you'll eventually run around half the internet crying how much legal hassle G2A puts their sellers through, making them look like as if they give an actual flying fuck about how much stolen and fake goods are sold there.

Or, you can show them a screenshot of an IndieGala account with a 40-pack bundle captured on the image, and telling them you intend to sell all 300+ games there. They will welcome you and the ludicrous amounts of potential market listing fees you will continuously pay them with open arms.