You can use our USSD service to accept replies back from your users. We must have a way to forward this reply back to you. We recommend using txtNation's long mobile number (VMN; Virtual Mobile Number) to make this possible.
You must use one of txtNation's long virtual numbers and specify it in the ID of the USSD message request.
When the recipient replies to your message, we will send this reply to the inbound callback URL.
Users will not be charged for sending this reply within the USSD session. It does not matter whether this virtual number is local or not to recipient.