Thieves broke into a luxury car dealership in the East Bay and made off with some valuable loot – but it wasn't cars they were after.
  
The break-in at the Mercedes Benz of Walnut Creek took place about two weeks ago and confidential customer files were stolen.

One woman said she didn't learn about this until Wednesday. 

Mercedes customer who wanted only to be identified as Allison said her lease agreement and other paperwork containing sensitive personal information such as her Social Security number, driver's license and bank account numbers were in the stolen files. 

"All they need is the key to my front door and they're pretty much set. It's horrible," said the Orinda woman.  

Thieves broke into the dealership on Parkside Drive sometime after closing on Thursday, Feb. 7.

Mercedez Benz said in a written statement that the thieves pried open an outside door then another locked door of the business office and stole files from locked cabinets. 

Allison said she got a phone message from the dealership and feels that she should have been notified immediately after the break-in. 

"When you trust your private information to a company, you expect them to safeguard it and to notify you right away. We're just really disappointed," said Allison.
 
Allison says the dealership told her up to 3,000 customers are affected.

"You're always worried and waiting to see what's going to happen. You just can't feel comfortable," said Allison. 

The dealership says it immediately reported the break-in to Walnut Creek police.

Sonic Automotive, which owns the dealership, said it will be help affected customers with a free credit monitoring service, a consultation with a fraud expert and placement of an initial fraud alert on customers credit files.