Hi megg,
Thank you for using the Support Forum. Please make sure that you are following the instructions for doing a muti-send. If you do not use the multi send function you will not be able to continue to add numbers. If you are using the multi-send feature and you can only add two numbers then please power off the machine for 30 seconds and then turn it back on and try again. if the problem continues please consider contacting your support centre for further assistance.