I have seen similar results from Google Display Network. Poor quality traffic, invalid clicks, click fraud, no conversions, ect. Display advertising is probably the trickiest channel to generate a profitable return on ad spend. But I disagree that online advertising will not provide value for you. There are numerous types of advertising on Google alone. A recent client saw this range in cost per acquisition from AdWords over a 3 month period:
Google Display Network $45.31
Gmail Ads $7.61
Remarketing Ads $11.45
Google Search Network $111.42
You can see how the channels vary on cost per acquisition. They have since doubled down on Gmail and Remarketing ad spend. I suggest you find a Google Certified Partner that meets your budget and marketing goals. They can help you test the various AdWords channels and measure your return on investment.