My mobile phone is a Motorola A780. Why does it automatically dial when I send a text message or store a number and cannot hang up?

First of all, you have to think about whether you have had this problem before, or whether you have had this problem recently. If you have had this problem since the beginning and now your mobile phone has not expired, you can get Motorola after-sales service. Check it there, and they will replace it with a new one after confirmation. If this problem has occurred recently, it means there is a problem with the internal main board of the phone, and you need to fix it. Thank you for your answer!