My phone keeps saying that it's charging when it's not

Sorry for incorrect phone model, but I couldn't find my phone model in the list of models, so I just went with the one that most closely resembles my phone. I have a T-mobile Revvl 4, and the phone says that it's charging when it's not and the screen just randomly turns black, and it's had issues like this for 9 months. I have to constantly turn it off and then back on again to get it to temporarily work again. However, then the screen just turns black again, and the issue continues. My phone briefly stopped having the issue for about 2.5 months. On December 14, it was raining and only a little bit of rain got on my phone, but not enough to cause any water damage. I'm not sure if it's because of the rain or not, but now it's going back to saying that it's charging even when it's not, and the screen is randomly going black again.