Multiple PayPal users have been incorrectly charged for purchasing Mac OS X Lion from the Mac App Store, with one user claiming to have received a bill of nearly $4,000 for the $29.99 software.

Customers told AppleInsider on Wednesday that they were charged $3,878 on July 28 in a series of 122 separate charges for $31.79 each. They said they reached out to Apple but have not been able to secure a refund.

"Apple blames PayPal, PayPal blames Apple," they wrote in an e-mail to AppleInsider. "They both are claiming to investigate, but I am stuck broke for three days now."

So far only users who have PayPal accounts connected to their iTunes Store account for payments have encountered the problem. Some who contacted PayPal said they were told that the multiple charges were made by the iTunes Store, while Apple has insisted to some that the iTunes Store only charged once.

"I just got off the phone with PayPal," user "JustinIowa" wrote. "They said that even though Apple has refunded the balance and it shows that in my PayPal account, that they will not refund the money back to my bank account. It will wait until it withdraws the full amount from my bank balance, then it will be refunded to my PayPal balance."

Some reported that they have been hit with overdraft fees and other charges because of the mistaken multiple charges. Some have also been left waiting days for the refunds to reappear in their PayPal accounts.

Currently available only on the Mac App Store, Lion got off to a strong start last week, topping a million downloads in its first day of availability. That's the fastest start of any operating system in Apple's history.