Product: Debt collection

I am getting contacted by a caller stating they are a processing department ( that's what they say in the message ) about a debt that I am not familiar with that is from XXXX based on what the person said when I called back. The first call came from a dialer on XX/XX/XXXX, and when I answer they provide a contract number- they do not announce themselves as a debt collector at first. I called back asking about the company and the contract and what it was about and at first they were forthcoming and said they are XXXXXXXX XXXX XXXXXXXX, but when they said it was an attempt to collect a debt, I asked for specifics, and they started giving me dates that the application was in XXXX and paid timely until XXXX and then just stopped. XXXX is not a time I would have been applying for credit cards, and they stated my employer 's name as a name that I've never heard of. The first time, I asked the person on the phone to spell the employer name, because I wasn't sure I was hearing correctly and was trying to XXXX it - the name they were saying was completely unfamiliar to me, so I wanted to XXXX it and see if it might have been a XXXX on an actual employer I may have had at some point, but the name didn't come up, and they wouldn't confirm the spelling and started getting hostile and asking if I'd been served yet ( which I haven't ) and telling me that they were going to contact my employer and take action against me if I didn't pay the amount they were stating ( around {$2300.00} ) and that if it went to court the amount was more than doubled ( over {$5000.00} ) and I would have to take up the dispute with the judge and pay the higher amount. I then repeated multiple times that I never had that card and would not have had any card during that timeframe and that the employer was not anyone I'd worked for - I repeated myself more than once, they kept threatening that they were calling my employer next and starting legal action, and then they hung up on me- I'm not sure why I would have been served if there was no legal action. I also told them I monitor my credit reports almost daily and that debt is not on my reports and again, not my debt. They called again XX/XX/XXXX, and gave a different contract number, so I called back and got a different group that said the debt under a different creditor name and then finally put me on hold and a different person picked up- it turned out to be the same person as the week before and eventually, the same debt as the original call. I again restated the debt wasn't mine, and she said she was calling my employer to start the process for garnishing my wages and made the same threats about legal action. I tried calling the company they said was the original creditor, Home Depot but that company does not have records back that far to see who submitted the application, and their dates did not match up to what the caller was saying for an application under my name- they found an account under the same name as mine that was charged off in XXXX, but they had no further detail that could help me figure out who submitted the application or when. The processor has called two more times in the last few days, XX/XX/XXXX and XX/XX/XXXX and I have not been able to answer- it is always a robocaller. I listened to the message, but I did not call them back. They left a message today saying this was my last warning, and next would be the call to my employer.