I dont know how to do any of this

i dont know how i get the purchased on my computer. I've gotten to where i see it but i don't know what to do when i get there. I dont see anything to click on. I need help. I need to get my money back for songs i accedenally clicked on when i downloaded my songs back after a update. the update deleted everything and changed everything and im still learning how to work it. I spent too much and I just need the money back. I didnt mean to buy it in all. I just need help getting a refund.