I think I can help you with this.

1. To answer your question, no AT&T does not sell or provide your information to any outside companies. It is against AT&T's privacy policy. Sounds like you got a recycled number, or may have posted your number somewhere online, as a result of this these kinds of telemarketers are calling you.

2. To block the numbers or stop them there are several different ways to stop them.

OPTION 1: If you are using just about any phone other than an Iphone, your phone has a reject list, or has an option that can be downloaded to block these numbers free of charge, such as Mr. Number for Android. The Mr. Number app is free of charge and allows you to either set your phone to block unknown numbers or just about any number of phone numbers that call you by either sending them straight to voicemail or picking up the phone and hanging up on them.

Option 2: You can talk to the telemarketers that are calling you and request that you are removed from their calling list.

Option 3: There are certain companies or conglomerates of telemarketers, sometimes scammers that once you are added to the Do Not Call list can still call you, One of which is the Direct Marketing Association (DMA), you can request to be removed from their services by going to www.dmachoice.org.

Option 3: Unfortunately the only other options I can think of to block these kinds of calls would be to change your number, if you call in to AT&T 1 800 331 0500 or by dialing 611, tell them your issue and usually they will change your number free of charge, There is usually a $36.00 fee to do that though. Make sure you check your voicemail before changing it because all your voicemail will be deleted when you change it and you will need to set your voicemail back up when you are done. Hope that helped.

Message back or PM me if you have any other questions.