We can't tell you as we don't know how it was added. It could be one of about 5 different ways it has been added.
Have you tired deleting the IPTV bouquets using the TV button and then the menu button, select remove.
If you do this and restart the box do the IPTV bouquets come back?
If you want it gone gone, flash your box and put on the image you are currently using.