No promotional discount - Discovery Miles

Hi

I received a promotional email from Discovery Vitality about a promotion at Sunglass Hut, whereby 15 000 Discovery miles can be used to the value of 20 000 miles.

After purchasing a pair of sunglasses in-store using my Discovery Miles, i realized there was no discount, i paid the full amount. I did email Vitality about this, have had no response as yet.

Please advise? Vitality No: ***