Just wondered if anyone else had experienced similar problems?
It is preposterous for them to say such crap as using Firefox causes it. My experience with Apple is that if you insist talking to a supervisor or manager , you always get better results than with a foot soldier. In the old days all the store staff were more empowered and resolved issues quicker and without quibble. These days it is a different story.
To give you an example, last week my mother-in-law went to Regent Street store as her ipod touch wasn't holding charge anymore just a little after a year of use. The guy she spoke to told her that as it is not under warrantly she needs to buy a new one. He also had the audacity to say to her that these things are meant to be used and replaced when the battery dies. I know for a fact that they have a battery replacement program but in order for mother in law to be convinced I called Apple support and spoke to them when she was present. They offered a battery exchange for £82 , which the tosser in the store should have done in the first place.
Don't give up, be polite and you will get results I promise!