How far back can I request a refund?

Apple typically doesn't show the app name when there has been a purchase and I assumed the purchases were valid. I had no idea that I was paying $9.99 a week for iPhone ring tones!!! and a few other apps for a year now. I know this was looked over on my end, but I was not checking all these purchases and my kids get Robux, so I thought it was an extension of Robux...Hundreds of dollars I've spent on apps not in use. I think with the pandemic I became disconnected from checking all my purchases. I am stunned that this has gone on and by apple not adding a description to the purchase on the credit card transaction is deceptive.