Thank you for your response. I opened the invoice but there was no payment to it, but the payment to that invoice still shows. 

This screenshot above shows payment but when I go into the invoice, it shows as the invoice not being paid. I have to delete a bunch of these as the person who entered these payments did so somehow even though they were already paid. That's why i'm trying to learn how to delete it and I will apply it to the rest of these and re-enter them.

Please note that there is nothing in "related transactions" on the right.

However, that payment is no longer in my "payments to deposit" window anymore. What do I need to do from here to remove it from the "Customer Information" window under the "transactions" tab? Thank you for your help with this.