There is no law against putting another company out of business through competition: anyone is allowed to compete for business, customers, market share, etc. and if in the process some other business cannot compete with them and goes out of business, thati is perfectly. What you can't do is use inherently illegal methods to put another out of business: intimidating customers to stay away, defamation, filing false complaints to the health department, hacking their account, fraud, etc. But if the methods, then the competition is.