Sprint I was sold new phone what uses 4g Lte and was not told that service is not available in Hawai'i. Honolulu Hawaii

I went to a local sprint store to get my current phone checked because I was having power and charging issues. I was told the phone circuits were corroded and I would need a new phone. Instead of replacing my Samsung Galaxy S2, which would cost me $100 as a deductable, I was convinced to upgrade to a new Samsung Galaxy S4 and pay $250. I was very unhappy after about a week of using the phone because it was not responding well, in fact my old phone worked better faster. I went to the Sprint store where I bought and they said that Sprint 4g LTE network is not available in Hawai’i and planning to be available at the end of the year. Okay that did not make sense to me because why would you sell these phone and not inform your customers that the service was not available so I called Sprint CS and they said the same thing and when I asked why Sprint would sell products in an area that does not have service for that product. The response I got was when the company release a product it is nationwide and she said that the 4g LTE will be available by the end of the year and would have to wait for it. I could not get released from my contract because I had passed the 7 days return policy. I feel I got ripped off because had I known this beforehand I would have gone with another carrier instead of renewing my contact with Sprint for another 2 years. I again called CS to see if they can waive my activation fee but not reply. I’m currently trying to find if there are others with the same issues and maybe we can get a class action filed.