Saysana

Anyone know anything about the ballasts and inverter where i can get either one for dirt cheap the dealer told me that their is a problem with my inverter. Because my left headlight is not working. I think their trying to BS to get me to pay them 700 dollars. Before i brought it into the dealer my left high beam was working since i got it back it doesnt work anymore and they say its the invertere. ANY MECHANICAL ELECTRICIANS or anyone who can help please tell me what I shoud do thanks.