AbanteCart is a free PHP based eCommerce solution for merchants to provide ability creating online business and sell products online quick and efficient. AbanteCart application is built and supported by experienced enthusiasts that are passionate about their work and contribution to rapidly evolving eCommerce industry. AbanteCart is more than just a shopping cart, it is rapidly growing eCommerce platform
I found out that in the account/invoice order cancellation URL is using order_id instead of ot for guest, so i copied the code from fast checkout.