Very good example of a difficult problem. The answer to it is not government. I always challenge myself and others with this: if you had a problem for which government seems like a very reasonable answer, can you design a better solution?
And indeed, you can. In this example you have to realize that what government is selling to consumers is the service of preventing eventual rise in prices after the competition is weeded out. If, as a consumer, I am worried about such predatory pricing as in your example, what is to prevent me from signing a contract with a company which specifically states "you are not allowed to raise the price"? Then this contract can be enforced by whichever private court and protection agency I hired (how this would work is a matter of a separate post, but I recommend reading "The Machinery Of Freedom" by David D. Friedman on that subject).
However, I don't really think you'd need that contract. What would really happen is that many companies would have infrastructure in many places (as is the case in my country) or you would have alternative connections (as, again, is the case in my country with a 4g operator Yota). Or you would have willing rich investors if they see that opportunity exists to disrupt the market. Finally, people may move and stop using the service if they dislike it.
There are all sorts of opportunities. Government is just one solution with a very high cost indeed: you have many people die in bloody wars which are run for your tax money and on your behalf (as is the case with both of our countries, I suppose). And no, however you wanted it, with government you can't have only the good things and none of the bad ones. It's logically impossible, because for a politician the economic incentives are always in the wrong place.