Before somebody takes all your money, you can probably get more help here, but you will need to have some clue about using a meter and what the inverter etc does and does not according to its specs (you do have its manual?)
If you can be very specific and answer the pointed questions with good pointed answers till the problem is pinned down we can get pretty close.
If you are hopeless at all that and need help, then try tech support at Xantrex (not always useful I am sorry to say). Or get an "estimate" or try to get some idea from some RV techs what to do before handing over your wallet to some outfit that "sees you coming."
"The other guys in the park" can often be ignored! :)