Not been given the free trial and charged twice

Hi, 

On the 15th September I activated my 7 day free trial of Adobe Lightroom. However, I checked my bank statement and found that I had been charged 11.99 GBP twice (so 24 GBP total). I researched online and found that if I cancel my subscription within 14 days I should be refunded, so I am planning to do this, but I first want to check that I will be refunded for the double charge. 

Perhaps someone could help me with this and answer a) why I was charged twice, and b) why was I not given a free trial? 

Thanks,

Sarah