I have a Samsung Galaxy Tab E & it won't charget after 24 hrs. I tried a different wall plug, wall chager block but I don't have another cable to try. I have 1 for an LG phone & it works on my galaxy S5 but scared to plug into my tabs port. Also I can't see how to open it to check/change battery or put in a similar card for data from att. Any reasons why this is? Getting really pissed it's only 7 most old but no warranty.