[Ruslan]

We made some fixes.
Please try to replace your classes/XLite/Module/CDev/TwoCheckout/Model/Payment/Processor/TwoCheckout.php file with the TwoCheckout.php in the attachments (make backup of the original file before the replacement).

Also we add logs for 2co. Make developer_mode = on in your etc/config.php file. Place order with 2co and check your var/log folder. There should be log files for TwoCheckout. Please, share logs with us.