App and subscription

Hi,  Can someone please help me!!!! 

I sigined up to quickbooks self emplyed and i am having terrible trouble with logging in etc.

I did the 30 day trial.  I have purchased the monthly subscription for £7.99 per month through my i tunes.  Valid until the 10th September. 

When i go back into the app to log in it comes up with a subscription again.  When i go on the PC to log in it comes up to say fetch my details but it justs doesnt load anything!

I am paying money for nothing, can someone help please!!

Thanks