Mail app on iPad not deleting emails

The mail app first made me re-register my google account which I did and it worked fine for a day. Then it required me to do it again today and I found both accounts selectable. I then deleted the most recently registered version and the original registered account showed again. Once started the mail app displayed the very last email in my account while highlighting the most recent. I hit trash and erased the oldest email by mistake. I then selected the most recent email by pressing it with my finger and it displayed it in the window. I hit the trash button and it takes me the oldest email in my account without putting the email I selected in the trash bin. Tried several times with same response. Then selected edit and trash of several emails and this functioned correctly. However, selecting trash for several emails remained non- functional.

Any idea what the fix is?

Gmail functions fine over the webpage or using android device. iPad mail app is the malfunction currently.

iOS 7on board with no updates available. Apps all up to date. Available space is available. 32gb apple ipad2 used for schoolwork. Critical asset which syncs to my online school files.

Thanks for support.

Best CJM