Now more than ever it seems debt collectors are some of the busiest people, and not always the nicest to deal with.
But, you do have rights to help you.
In 1977 Congress enacted the "Fair Debt Collection Practices Act" which sets guidelines debt collectors must follow on how they are to conduct themselves when collecting a debt.
Many consumers are unaware of these guidelines and can/will often be manipulated by collectors who use unlawful or make use of emotion-evoking tactics.
Intimidation or threats are not allowed nor is trying to manipulate you into paying a debt.
Some helpful tips and what collectors cannot do:

• Contacting a consumer without his or her permission outside unusual hours, place or a time or place known to be inconvenient to him or her.
  
• Call the consumer on the phone without identifying themselves.
  
• Contact the consumer at work if his employer disapproves.
  You will need a proof letter stating that your boss/employer disapproves.
  Send the letter to them Certified Mail - Return Receipt Requested to prove they received it.
  
• Contact anyone else about a debt except the consumer.
  The only exception to this is if they are attempting to verify a location/address.
  They can call neighbors, friends, bosses, family, etc.
  to obtain information.
  
• Harass you the consumer, his or her family, friends or employer.
  It is a psychological game.
  They log everything into their computer's database.
  Everything you say or do will be documented.
  Harassment is typically multiple phone calls in a day.
  
• Use inappropriate language, including threats.
  
• Collect any amount greater than your debt unless allowed by law - may include interest, court costs and attorney's fees.
  
• Ask for or accept a post-dated check or other instrument post-dated by more than five (5) days, unless they notify prior to deposit.
  Do not give them electronic access to your account.
  Don't send them checks from your own account if they have harassed or lied to you.
  Use a money order instead.
  
• Deposit or threaten to deposit your post-dated check prematurely unless they notify you in writing of their intent no earlier than 10 days or less than three (3) business days prior to the deposit.
  
• They must apply any payment received toward your debt.
  

Collectors can contact you the consumer by phone, mail, in person, by fax or email during reasonable hours such as between 8:00 am and 9:00 pm (the consumer's time zone) week days.
Weekend are usually off limits, unless the cosumer give the collector permission to call at that time and then it's hard to take back.
The bottom line is this, you have to know your rights and obligations as a consumer.
Get all agreements in writing (fax, email, mail) before you begin sending any payment! Keeping good records can also help you.
Record when you talk or contact them, is it by phone or mail, the date and time, what was said and so forth.
If you end up in court, your record keeping might just help you make your case, especially if a collector ever over steps your rights and what they are able to do.
Knowing your rights will only benefit you in the long run.