Sounds like water in the switches, based on what you've said. I do not cover my switches when washing the bike (and ride in the rain), so not sure how this happens, exactly, but sure sounds like the issue. I would get some compressed air (dust-off) in a can and give that a go, since you don't have a compressor. I'm not familiar with the spray you used, but would think WD-40 might help after thoroughly drying out the switches and then blow it out again. I think water out and it'll behave. I'd do all this before writing off all the electrical components and before resorting to taking it to a shop. Btw, how many miles are on your bike?
I realize that basic maintenance is not for everyone, but if you can read a recipe and cook, you can do your own oil change. You're going to ride nearly 300km (time/gas) and then wait for someone else to do what you can definitely do yourself in less time, with the oil of your choice, and much cheaper. You should consider it- there are many posts here about it and it's well documented in the maintenance manual (located in Resources- top of this page). It's not (sorry)..... Rocket science