To calculate the total amount of payments received, report on payments, credits, refunds (and reversals). In doing so, CampSite will calculate the total amount of payments and credited payments, minus any refunds and reversals, for the net amount of total payments your camp has received.
To do that, generate the Transaction Log where the only "Transaction Types" selected are Payments, Credits, Refunds, and Reversals. Apply any additional filters if desired, then run the report. Scroll down to the very bottom of the report to see the grand total.
For more information on using the Transaction Log, please click here to read our support article.