How can i remove the container which is stuck?

Try the following site
www.thetford.europe.com
www.thetford.com.au for those in Australia
the sites now have repair instruction pdf downloads.
On europe site select engilsh then customer service take it from there for access to the pdf downloads or you could contact 'ask thetford'. If my memory serves well select [repair instructions, built in toilets, your model then you should endter the pdf download lsting.

I have a horrible thought you hand't closed the blade properly before removing the holding tank if you are refering to the container. or the knob for closing had been turn to open or half open position. Contact the 'Ask thetford' section they may come up with a safe less expensive solution' as I don't think that is covered in the downloads.

Bob
May 2009