My business is losing sales?!

Hello, I own a cell phone and tablet repair business. I feel like I am losing customers. Here is what is going on. A customer will call me and ask about a repair price, I ll respond for example "Iphone 6 screen repairs are only $79.99"
And they will say thank you and then hang up. I feel like there is something I am doing wrong. My prices are more affordable then every other repair business around and I feel like I am not getting that across my just telling them the price. Anyway, this is my question, I am asking this to sales people. How should I respond to this? And why do you think they right away say thank you and hang up?
Added (1). Also, what can I say to make them come into the store. I just need them in the door.

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