There seems to be a difference between the available Store Credit of yours with the site currency you had picked previously. Would you like to:
Fortnite ACCOUNTS USD $3.44
Fortnite ACCOUNTS USD $18.25
Fortnite ACCOUNTS USD $3.22
Fortnite ACCOUNTS USD $49.99
Fortnite ACCOUNTS USD $29.99
Fortnite ACCOUNTS USD $7.99
Fortnite ACCOUNTS USD $3