After a couple of months, the batteries won't come out

I wanted to like this case. I loved the idea: small startup has design and relies on KickStarter to fund it. Huge success comes via several blogs getting the concept out to their readers. When the Weiter arrived, it was flawless. It beat out my other cases for my daily use case due to its versatility and clean lines.

Now we come to a problem. I went to change the batteries today, and can't get them out. The material used for the battery tube is so corroded that bang as I may, I cannot get the batteries out. I've tried nail files. I've tried bamboo skewers. I have banged it open side down on a table, and finally dislodged the battery closest to the end, but the other 2 will not budge.

I guess this one goes on the shelf of disappointments from over the years. Right next to the Nextbook 3 I think.