This is what I would view as a significant material change in the company's operations.
The company states that United Digestive accounted for 20% of the company's operating EBITDA and a significant portion of the company's revenue.
Right now an investment in the company, and more importantly for you a decision to hold the stock, now depends on their ability to recoup that revenue and EBITDA. The company states it should be able to replace the EBITDA and revenue through acquisitions and organic growth through 2021 (the loss of the client won't actually take effect until 2022.) However, whether or not they'll be able to do so is another question. As we saw with Riocan and its distribution cut, whatever management states should be taken with a grain of salt.
Then we have to factor in that even if the company did replace all that revenue through acquisitions and organic growth, those acquisitions cost money AND we've essentially spent a year just trying to recover what they've lost.
It would be a pretty hard pass for me on purchasing this stock right now. This should emphasize the risks of a company relying so much on a single client though.