United Cash Loans Called me at my place of employment threatening me and was very harsh! Internet

A man claiming to be a collection agency for United Cash Loan called me at my place of employement and was very rude and when I told him I worked for a call center and would have to call him back after I got off work at 5pm, he still kept harrassing me about the loan I took out. United Cash loans was supposed to take out installment payments on the last day of the month when I get paid but they took the first payment out a day early and when I mentioned that to the man calling he argued with me and I can not have this company harrassing me at work!. The man did say they have tried to contact me but not one person from the company has ever left a message on my voice mail for me to call them back and when I look them up online there is not a phone number to call them that I could find so I placed a stop payment to them since they have not carried out their end of the agreement! The man got very rude with me and asked what I was going to do about the $350.00 dollars I owed them instead of letting me call him back after I got off work to make arrangements so I asked how much and then hung up on him. I work for a call center and can not tie up the phones on personal matters so I had to hang up on him since he would not stop harrassing me! I came home and tried once again to look up a phone number to United Cash Loans to call and straighten this matter out but could not find a number for them. I know how customer service reps are supposed to act over the phone and will never be talked to like the man calling me talked to me. Thank You