Unknown charges. – Portrait Blur - Free Lens and Depth Effect Bokeh Review

I’ve been charged $5.33 for four months without realizing it (because I never authorized the charges) after deleting the app four months ago. I have tried to unsubscribe from the “automatic renewal” by going to the app support and have had no luck. I have also downloaded the app again to find an unsubscribe option, but there are no settings if you don’t have a paid account. I don’t understand how this is happening, but I’d greatly appreciate if the app creators of apple could help me stop this charge.
Review by JORK19 on Portrait Blur - Free Lens and Depth Effect Bokeh.