Why Apple charged me for twice in billing receipt when I bought handful coins of Gems Fashion icon then asking my password but after 2minutes the connection was error and no added coin so I tried to buy coin again and successful but apple charged twice

Why Apple charged me for twice in billing receipt when I bought handful coins of Gems Fashion icon then asking my password but after 2minutes the connection was error and no added coin so I thought it doesnt work and apple won't charged me in first transaction so that I tried to buy coin again and successful but apple charged twice in my billing, so what can I do? So there's one billing that is wrong and how can I do to get my money back.