Attempted to buy a ticket online in the evening at Heathrow, as no ticket machines or National Express office that was open. Website crashed but payment was still taken - and no ticket issued! Tried again but the service no longer appeared on the website. This all happened just minutes before the coach was due, inducing a great deal of stress as the next service was two hours later. Not ideal after 24 hours on a plane and a family in tow. Absolutely no one from National Express around to help. This is Heathrow, not a village bus stop! Managed to buy a ticket through a third party at the very last minute but had to pay a £5 fee on top - outrageous! Original money was put back into my account, but National Express will not refund the extra fee that I had to pay, which would have been the right thing to do, if only to show a decent level of customer service. Way too stressful - I will take the train instead next time. A shame as it could all have been so easy...