Product: Debt collection

I received a call on XX/XX/2019 from a company calling themselves XXXX XXXX. The lady was rude and said I owed {$1700.00} I told her I had no knowledge of this debt. She said it was for an XXXX store card. I asked her could she send me written correspondence of this in the mail. She became upset and said shed sue me and asked me to give her either my bank account information or a debit card to make payment arrangements. She also asked for my social security number and I told her I didnt feel comfortable giving that over the phone to a company I wasnt aware of. I told her I was not giving her my bank information because I had never received anything in the mail from this company and that I wanted to get something in the mail from them with the amount and the name of the original creditor and that I wanted to call XXXX myself to get that amount to make sure that it was correct before I made any type of payment arrangement with her. Then a man came on the phone and he started being very rude to me. He didnt introduce himself, he just started talking. I asked who are you? He said he was her manager. I told them both that I knew my rights and I was entitled to ask for written correspondence before just giving me bank account information over the phone to a company I never got a letter from. They started telling me that they would sue me so said Im on vacation and I had gotten upset because I was at lunch with family and was visibly upset because this man and woman are screaming at me in the phone threatening legal action and threatening to garnish my wages because I asked that they send me an official letter. Im a mom of XXXX and help my mother who is going through XXXX XXXX. I dont have. {$1700.00} to just give at one time. I gave her my address because I moved and she said shed call me again. I still have not received a letter as of XX/XX/2019. She called me again on XX/XX/2019 and I told her I would contact them once I receive a letter from them. It had only been 2 days and I said I should get your letter this week and I will call them once I did. She was rude again. My mother text me on XX/XX/2019 telling me someone name XXXX from XXXX called MY MOMS CELL NUMBER looking for me about a follow up call for collection for a debt. Why are they calling my family discussing my financial matters!? I dont know how they got my moms cell number. I dont live with my mom. And I never give any company my moms number. They wont validate this debt by sending a letter and they are calling my family which is a violation of the Fair Credit Reporting Act and they certainly can not contact my family. I called XXXX XX/XX/2019 to ask them who their third party collections company is and they gave me a number for a completely different company. XXXX also told me not to give anyone my Social Security number or bank information if this collection company wont send me a letter. I asked them to also send something with the amount owed so I know the collection company isnt telling me the wrong amount and XXXX told me they can not? Im not trying to dodge these people but I want to make sure I get official documentation before I just give a collection company my personal information. Especially when a company claims they are legit but talks to people in such an unprofessional manner. I didnt know that by me asking for an official letter would warrant me bring harassed, threatened with legal action and my mom with XXXX being called.