This number texted me. They simply said "save my number". I inquired as to who they are. No reply. I have a feeling it's a very scummy debt collector. I got in trouble with a payday loan about eight years ago. Despite paying my debt, they continue to sell it to shady debt collectors. I've been getting voicemails from similar numbers saying they are investigators who are coming to my house. Creepy people.

FYI, NEVER pay any caller - let alone anyone who texts you - who refuses to MAIL a debt validation letter showing you owe the debt and that they have the legal right to collect said debt.  Remember that the debt collector bears the burden of proof to show you actually owe this money.  Refusal to mail a DV letter within five days of the initial call to you is a violation of the FDCPA.  Claiming to be "investigators" who are going to come to your house is also a violation of the FDCPA.  Please do report such callers to the FTC, FBI, Department of Justice and your state's Attorney General.