Check your mail, AT&T wireless customers — you might have an announcement from the company disclosing a data security breach that happened two months ago. Snail, mail indeed. AT&T confirmed over the weekend that three workers at one of the company’s vendors accessed an undisclosed amount of AT&T Mobility customers’ records.

It’s unclear why AT&T took this long to alert customers as the breach reportedly took place in April and was discovered in May, the Atlanta Business Chronicle says . The company is also keeping mum on exactly how many customer’s accounts were affected.

But according to Re/code, the company has admitted the breach and has apparently sent customers a notification in the mail.

Re/code has a statement from AT&T’s executive director for media relations, where the company says:

“We recently learned that three employees of one of our vendors accessed some AT&T customer accounts without proper authorization. This is completely counter to the way we require our vendors to conduct business. We know our customers count on us and those who support our business to act with integrity and trust, and we take that very seriously. We have taken steps to help prevent this from happening again, notified affected customers, and reported this matter to law enforcement.”

You might want to start checking that pile of junk mail now, folks. Because without that piece of paper, you might never know if your electronic information was accessed.

AT&T Phone Records, Social Security Numbers Hacked [Re/code]