Shoe booster benefit not paid.

I wanted to take advantage of the shoe booster benefit, so I activated Vitality healthy gear. I then went and bought a pair of running shoes. A few days later I realised that I also had to activate the shoe booster benefit. I did so, and on 2 January returned the Salomon Speedcross 4 shoes that I had bought on the 27th December. I then, in a totally seperate transaction bought a pair of Salomon XA lite's. When I did not get my cash back I phoned Vitality and logged a query. Their response was that the Speedcross 4's that I returned cancelled out the XA lite's and that I in fact did not qualify for the benefit because of that. The query is now in the hands of a manager, but honestly, I do not know how the people who have looked into this could come to this conclusion. The Speedcross 4's were bought outside shoe booster and when they were returned they should have had no effect on shoe booster. Yet according to the sparks at Vitality essentially my shoe booster 'balance' went to R-2000 when I returned the speedcross 4's.