Shell 10x Airmiles. Ripoff?

[TreeGuy]

I've put quite a few hard miles on over the past few years and have gone out of my way to take advantage of Shell's 10x promotion.

Retail staff have repeatedly assured me that it's one mile for every $20 spent so long as you exceed 25l. The 10x is then applied. ie I put in 100l it should be 5 Airmiles then multiplied by 10, equaling 50. Nope.

I just checked our account out of curiosity and this deal hasn't seemed to have been honoured.

Hypothetically, I've spent enough to take my family on vacation. The Airmiles accumulated in no respect represent what should be there.

Shell's disclaimer is somewhat convoluted, but appears legit. Anyone able to provide a bit of insight? (YES, I called them but it isn't within business hours and I want to know NOW! Lol). Am I getting ripped off?

Thanks in advance.

Tree