I'm having trouble with my phone speakers

So I got this phone for like a year and a half ago and it been working fine, the phone is Lenovo A6000 Android Lolipop. Anyways one day I woke up and I wanted to go on YT but every time I go on any video it says Video playback error try again… So I didn't mind thought maybe watch something on phone. But it didn't open as well. Like I press on it and nothing happens. Until then I figured out the speakers are not even working cuz I opened a game and I didn't hear any sound. I tried to reboot my phone it took long to reboot for the first time ever. And it showed a black screen for like 5 mins and its back normal. I tried the speakers. Still nothing. So I tried going on Dolby Audio. It doesn't launch… And then I noticed even my Cellular ain t working. Took forever to get it back and then tried to call somebody it doesn't call. Got my brothers phone to call myself it doesn't receive calls… So I decided to erase everything thought it has a virus or so. So I did and got a new phone had to setup everything over but still the same problem! Please somebody help. I don't have anything else except this phone for entertainmemt