Why can’t I remove PayPal from my account? PayPal owes me hundreds of dollars and of course they don’t admit it and all I did was use a free trial and it was free!! I keep getting emails regarding my account!

Why do I keep receiving emails regarding my account information when PayPal is on there yet they won’t let me change it?? And PayPal owes me hundreds of dollars and won’t admit or return messages! And apple keeps telling me I need to update payment information when I don’t pay for thing’s through apple and I did try a free trial music app and shouldn’t be billed!! So why do they keep hassling me?