Worst period tracker

Ive tried several trackers when I get new phones, just to see whats out there. This is the worst Ive ever tried. I did not have a period in the month of September, so it put one in for me and I cant delete it. How am I supposed to keep an accurate record when it does that? Also, it never lets you look at your calendar without first making you look at an ad and THEN making you look at another ad for their paid version of this ap. Who would buy this ap if it doesnt let you keep accurate records?

Wintersillusion about Woman Calendar-Period Tracker