Fast-growing Canadian technology company Lightspeed is pushing back after a short seller alleged the company has misled investors about its financial health, causing a $2 billion plunge in the company’s value.

On Wednesday, Spruce Point Management, an American short selling investment firm with a history of targeting Canadian companies, put out a lengthy report on Montreal-based Lightspeed Inc., alleging the company has covered up “massive inflation” of how many customers it has, how much money it makes from them, and how much growth potential it has.

Lightspeed is a payment processing company that helps small businesses sell things online and in person.