Mail tampering or am i over analyzing things?

Iv been at my new home now for about two months and iv had problems with my mail ever since i changed my address.im not sure if its the mail man or my neighbor.it started with a letter that came a day late forcing me to reschedule an appointment.then when i started not receiving my netflix dvds.they were being returned.i called the post office and someone said they would make a note of it.well yesterday i received a call from my phone company telling me that they sent me a bill that was forwarded back to them and that i need to give them a call.my neighbors arent so neighborly.they have given me grief ever since iv been here.oddly my pomeranian of two years has disappeared after numerous and false complaints have been filed on my yard dogs.iv never spoken to them because they started on me after my second day of being here.i trully have a feeling that they may be forwarding my mail back somehow.which means they are in my mailbox.btw i dont recieve anymore mail from the previous tenants either which is odd bc i never forwarded any of it.am i reading too much into this.