Headlight Switch problems of the 2009 Toyota Camry

Parked car in driveway two hours later my neighbor told me my lights were on. Light switch was off could not get lights to go off. Called tow truck they could not get lights to turn off, so they pulled the fuses for the lights. Three hours later the horn started blowing,,had to disconnect to get it to stop. Took into Toyota dealer where I bought it, a year ago. They said they thought it was a after market alarm system that was installed previously to my ownership. They disconnected it, three weeks later same thing started happening, except this time the high beam headlights would not turn off. Take it back to Toyota and now they say it is an internal electrical problem that may cause other problems if not fixed. Around $825.