The makers of roundup, Monsanto bought up all the generic company's rights to make the product. So now Monsanto owns all of it and they raised the price.
Someone told you a fib. That has nothing to do with why the price went up, as I understand. The patent ran out a while ago and many companies are producing glyphosate.There are a number of reasons the price is up from a few years ago, but they all come down to supply of chemicals to produce it.