Get inbound calls to Freeswitch working

I am unable to get calls from PSTN to freeswitch working. Calls from a SIP user into the switch (over the gateway) work. Calls between extensions and outbound calls work. I'm loading dialplan, configuration and directory with xml_curl (I had used a lua xml_handler script). I can confirm there is no problem on the carrier end...same carrier works with other freeswitch, asterisk and fusionPBX installations. The task is to look at my setup, determine the problem, provide the solution and provide documentation of the problem and solution. Note 1. You have to solve this problem using the standard approach. Any solution that does not involve the dialplan "transfer" application - from the public context to the "internal" context is unacceptable. 2. This is a multi-tenant setup. 3. Because I'm loading configuration on the fly with xml_curl, the solution has to factor this in i.e static configuration (XML files) will not be acceptable. 4. On the back of 3, working knowledge of Python/Django will make this a quick transaction. You can get in touch for more info. *DoubleNote*: If you don't have an idea of this problem (or solution), don't bother wasting both our times. Thank you for understanding.