Is this misrepresentation of your discounts???

I feel very let down by your advertising process Basha/Birkenstock. I was very keen to buy your silver bend low sneakers, repeatedly advertised at 36% discount. When I went to 'check out' they had jumped back to full price. When I phoned their contact Centre I was told 'that the discount it doesn't apply to all sizes'. This should be MUCH clearer in the adverts to avert disappointment and frustration. I tried about 6 times to check out :(