I've completed my esa50 from (well my daughter has) and I've left the space for my phone number blank and said for all contact to be made in writing. Has anyone else done this? I'm not sure if this is allowed so I just want to make sure that it's okay.
You are perfectly within your rights to do this - but be aware that the DWP might well have your phone number on record for some reason and would then be likely to use it, whatever you put on the form!
Nothing on this board constitutes legal advice - always consult a professional about specific problems