Hey there, Mqoe__.
What's the device you are using your memory card with? Is it a mobile phone? If "yes", I'd recommend that you try connecting the memory card to a computer in order to see if it's properly recognized and backup all the data which you wish to keep. After that go ahead and plug it back in the phone and reformat it, to see if you'd be able to put data on it and use it without an issue.
Hope that helps.
Boogieman_WD