My name is***** am sorry to hear that you are having this issue.
I will be glad to assist you with this.
Here are the steps to follow.
Open the book you want to read.
Press the "Menu" button to open the contextual Kindle menu.
Select “Change Font Size.”
Adjust the font size, typeface, words per line and line spacing in the pop-up menu.
For the Kindle Touch
Open an item for reading. The Kindle Touch uses contextual menus.
Tap the top of the screen to open the toolbar. Touch the “Aa” button.
Select “Font Size.” Select the font size you want to use.
Touch the “X” icon to return to your reading.
Please reply and let me know if you need any other assistance.
Also, please take a moment to rate my service by choosing one of the stars at the top and click on submit.
Thank you very much!