Who called from 6237381357

Why does this number keep calling, they will not say who they are. does anyone know who these people are and what they could possibly want?

Received a call from them today saying they are Merchant Services and there was a change to our account.  I can't figure out what account they are talking about and wouldn't tell me because they asked for the owner of the company, which I wouldn't let them talk to him because I'm guessing it is a sales call perhaps?

Update:  They are a company trying to sell us their service to process credit cards.