ACCO had much less debt 5 years ago, yet free cash flow was about the same as it is now ..... so maybe management has made some poor acquisitions. I don't know the details of the business history, but when a stock grossly underperforms the market over a 5 year period, it's worth investigating. The market is telling you something.
The chart does look oversold, so maybe you got a good entry point for a trade. Good luck.