This narrative, to me, is not understandable.
Did the converter smoke and give you problems when plugged into the mother in law's house or later, somewhere else? This statement--"Unfortunately, it is too far to get answers or help from the electrician used" makes me think the problem occurred later, somewhere else than your mother in law's house. If so, then all the 120V--miswired 220v advice can be disregarded.
Do you have a battery in the travel trailer, now? If so, and if it is charged, you should have 12V power to run everything. If not, you need a battery and shouldn't be on the road without one.
If the above is correct, you need to get a battery and probably, a new converter. You can check to see if the converter is working by measuring the output voltage of the converter across the battery terminals. it should be at least 13.2V.
