IS EDF ALLOWED TO TAKE VAT OFF MY WARM HOME DISCOUNT

I originally with Green Energy network. Then out of the blue on a Monday morning they were declared bankrupt without warning to there staff and customers. Ofgem then referred all customers to EDF. 
The referral has been one big headache the company had gone into registration and referral only completed last month. 
My late WHD was then applied in which they have paid £140 and deducted £6.67 VAT, leaving £133.33 is this allowed. I thought WHD was means tested benefit for those on low income or certain benefits. Is VAT allowed to be deducted from your balance by energy company