Paid for 1500 extra credits, got nothing

I wanted to buy 500 extra credits, this didn’t work (see error message on screenshot). I tried again with 1000 extra credits, also didn’t work. Now I paid for 1500 extra credits, even though I only wanted 500. Still I was charged twice. Can you please refund the purchase of 1000 extra credits and provide me with the purchased 500 extra credits?