glitch??

I frequently set up appointments in ICal on IPhone 5 ver 7.0.6. The problem is that they change unexpectedly. For instance I'll put in an appointment for a week in the future at 10 am with alerts. But a couple days later I'll look at schedule for that day and the appointment will have changed to 3:30 pm. This has happened multiple times. It does not change days arbitrarily but will change the time several hours. There is no consistency to how many hours it moves either backwards or forwards. Frustrating. Can someone tell me where to send this possible software glitch problem so Apple can take a look?

Thanks,

Mike