In June 2010, Apple and AT&T's servers were overwhelmed when they received 600,000 pre-orders for the iPhone 4 -- 10 times higher than a year earlier for the iPhone 3GS. AT&T (T) suspended preorders, and people who came into stores were forced to reserve devices using pen and paper.
A day later, Apple acknowledged its customers' frustration and issued an apology on its website.
"We apologize to everyone who encountered difficulties, and hope that they will try again or visit an Apple or carrier store once the iPhone 4 is in stock," the company said.
Apple said the number of preorders was "far higher than anticipated." In subsequent years, preordering has gone much more smoothly.
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