Apple smart battery case issue!

I have an iphone 6, and i've been using the smart battery case for about 1 year now. Everything was fine, until yesterday when something very strange happened with the case. I charged the case with the phone through the night, and used it normally the next day. By the end of the day, i noticed that, both the case and the phone had 100% battery remaining, wich is impossible, because i used it through the entire day without charging it! Now, both the phone and the case are stuck with 100% battery. Whenever i try to charge the case, the green led lights up, and the battery case starts overheating immediately. And it affected the iphone too. It always shows 100% battery, even though it doesn't have any battery at all. The only way i can use my phone, is through the ac power. If i stop charging it, the display will show 100% battery, but the sistem will simply turn off after 5-10 min. Now what should i do? Both the phone and the case are out of warranty, and one apple original accessory just fried my Iphone. I've always used original chargers and cords, like i have with all of the iphones i had. This is the first one to give this problem, wich was most certainly cause by the smart case. What should i do next???