A message keeps appearing in my inbox even though if I take off the sim card.

[AC Question]

The Same message keeps appearing in my inbox for hundred times. Let's just say 150 messages coming from the same person in one hour. My friend texted me something. One day later, my phone was hanging, I can't even press anything on my phone so I decided to take the battery off and turned on the phone. When I turned on the phone the text message of my friend keeps appearing in my inbox. Not only once, twice, thrice, but for hundred times. I asked my friend personally If she texted me for repeated times with the same message, then she said no. Even though I deleted the message, seconds later it appears again continuously. And it is really very disgusting for me. Ads keep popping up and even if I press the "back" button of my android phone it won't, neither the "home" button. And what happens next is my phone was hanging. So I was forced to take the battery off without shutting down first my phone. When I turned on the phone, the same happening again. The same message keeps appearing in my inbox, even if I I toggled off my sim card. At that time, I got a feeling that the problem is not on my sim card, but on my phone. Does anyone know what type of problem is this and how I could fix it? Thank you!.