OK, I would try to split the problem to decide whether it's what is being shown, or what is viewing it.
1) Try to access the mobile Joomla site with the device and check that that is showing a different view from the one you see from a desktop browser.
2 ) Then go through the backend of the site checking that the mobilebot plugin is enabled and the modules that are for mj_pda_xxx are enabled. Then check that the mobile pda template is chosen in components > K M J settings > Smartphone. If all looks OK I would make a note of the settings and then try varying them until something works.
I have heard that other Joomla extensions can conflict with MJ, so you might try turning them off one by one until you identify which one is conflicting.
If your site has advertising put on by the host, this too may conflict with Mobile Joomla.
Sorry I can't be more specific.
PS I just remembered, in MJ 0.9.8 in
components > k MJ settings > Global settings > User agent checking this has a drop down menu which may have been set to something which is causing the problem. And then it may be that the WURFL database is not working...