no stock for a month?

I've been a client of virgin for over 6 years now with minimal issues until recently .my contract expired and virgin politely called me to arrange an upgrade, i chose the iphone 6 as was on offer only to be told they are out of stock but promised delivery within a week, that's now 3 weeks ago and after many calls from myself they istill have know idea when stock will arrive, please can someone kindly address this urgently. I will not down grade to a lower quality phone due to your bad planning and poor procurement.