Are they free events? Free events shouldn't require payment.
If not, what about switching your payment module over to offline payment? And, if you don't want payment option to appear, you can try the following css added to media/com_eventbooking/assets/css/custom.css to hide it:
Code:
#payment_method_container {display:none;}
James Riley .: EventBooking user since 2014 ::: JoomDonation user since 2016 :.
.: grfx & web design / IT / AV @ St. Therese Institute of Faith and Mission, Bruno, SK, Canada :.
