It is pretty simple though really, in what world do you tax a company more and add costs to them which results in them protecting their profits, paying their staff more and protects their ability to employ more people?
You could probably say well they would have to accept that they won't make as much profit, that shows they are anti-business policies I'm afraid.
The reason things will cost more is also simple, businesses will pass on any increased costs to the customer. There is no policy I have seen from Labour that will result in lower costs for businesses so it is reality not project fear.
The reason Labour have come up with these kind of things anyway is because they aren't interested in business given they have people like John Mcdonnell who want to bring down the capitalist system.