In file oc-content/themes/gum/class/payments_pro/user/menu.php line 91
Change from :
printf('<li><a class="searchPaginationSelected" href="%s">%d</a>'</li>, osc_route_url('payment-pro-user-menu-page', array('iPage' => $i)), ($i + 1));
to
printf('<li><a class="searchPaginationSelected" href="%s">%d</a></li>', osc_route_url('payment-pro-user-menu-page', array('iPage' => $i)), ($i + 1));