Working from distance as a postdoc for a Company
Only the company can know how much they're prepared to pay, so we can't answer that. It could be more than the postdoc salary, it could be less. It could be higher, but for fewer hours. A consultant position might come with much fewer benefits. You really need to negotiate this with them. 

For the future, you'd ideally negotiate this with them before you begin to work. If the company is unscrupulous, or if they didn't give the green light to start the project, you might never get paid at all for the months you've worked. If there is an actual written contract it's much harder to pull stuff like that.