Fraud calls? Pretending to be AT&T asking me to give PIN numbers from "AT&T free message" texts
I got a call from **** a Jeff [edited for privacy-please do not post personal or unique information such as but not limited to full names, employee ID numbers, email addresses, phone numbers, account numbers, etc.], claiming to be AT&T employee. He said that someone (I don't know this person) had ordered 2 iPhone 7+'s on my AT&T account to be delivered to an address (not any address associated with me). I told him I did not place the order and that's a fraudulent order. Jeff said ok he'll cancel but he need to first send a PIN code to my phone and ask me to read the PIN code to him. I received a text message from (746) 118-88 saying "AT&T free message: Please use this single-use PIN to complete your AT&T Messages log in:asnpmh"
I noticed also that 2 months ago in April, I got another phone call someone claiming they are AT&T telling me that they noticed some suspicious calls, someone had made hundreds of calls to Russian using my cell phone number. Also not my calls and he offered to cancel them but need to send PIN's via text message to my phone. I gave him the PIN's and he said those charges are canceled.
This is a fraud? And what can they do?