In your case I would appeal the refusal you've had.
IPSEA have a specific Tribunal line; did you try this number?. I know all too well that their phone lines get clogged up (the usual demand and supply problem).
Tribunal advice: 0845 602 9579 Mon, Wed and Thurs 10.00 1.00pm Next-step advice on SEN appeals and disability discrimination claims to the Special Educational Needs and Disability Tribunal. When you call we will assess whether you need casework support.
My advice if you cannot get through to IPSEA is to use the services of SOS;SEN or ACE (as both of these are indepedent too).