I'm sorry to hear that your Saxenda pen isn't working correctly. We have had some patients get in touch with similar issues, and it turned it to be an issue with the needle used, rather than the pen itself.
We also have common reports of pens being unable to dispense medication following a pressure build up in the pen caused by the patient repeatedly pressing in the button at the top with no needle attached, or the needles not being properly attached to the pen. To resolve this, priming the pen and replacing the needles will allow this pressure to leave the pen and allow for the flow of medication.
Please could you try a few different needles to see if this helps? By all means, if you try this and it is still not working, please do let us know and we will be able to help further.