Can't format microSD card

Question

I am trying to format a microSD card. I have tried (unsuccessfully) erasing the memory from the Settings menu on an Android device at my disposal and now I have plugged the USB and givin it a go from Ubuntu (I can't use Windows).

Every time I try to format (or manually delete) data, every file and directory seem to stay put.

I thought it could be a microSD card corruption problem, but as I type

sudo fsck -a /dev/sdc

The only warning message I get is:

0x41: Dirty bit is set. Fs was not properly unmounted and some data may be corrupt.
Automatically removing dirty bit.

Then I issue the command one more time and the check is fine.

I've realized that the microSD card is on write-lock. Here it is what I have tried so far with no results whatsoever:

• put the microSD into an adapter and mechanically slide the the switch to unlock;
• manually changed permissions as root;
• gksudo nautilus in order to remove files;
• fsck.vfat -v -a -w /dev/sdc to try format the card;
• sudo cfdisk /dev/sdc to erase the partition

I am out of ideas, can anyone please help me try to sort this out?

Update: Running gparted I get this new piece of information

plain floppy: device "/dev/sdc" busy (Resource temporarily unavailable):
Cannot initialize '::'
mlabel: Cannot initialize drive