Those calls are Denial of Service Attacks or commonly know as a TDos attack on your phone lines.
Here is the info below on what the scheme is about and how it works. Futhermore the information on who to contact is below as well. Good luck.
APCO BREAKING NEWS
UPDATED BULLETIN – TDoS ATTACKS
As part of a coordinated federal response to Telephony Denial of Service (TDoS) attacks, APCO International is sharing the following update and seeking your cooperation in assisting DHS, the FBI and other agencies. This update is from an earlier posting by APCO International on March 13, 2013 to provide additional details of how to report attacks to the FBI.
Background: Information received from multiple jurisdictions indicates the possibility of attacks targeting the telephone systems of public sector entities. Dozens of such attacks have targeted the administrative PSAP lines (not the 911 emergency line). The perpetrators of the attack have launched high volume of calls against the target network, tying up the system from receiving legitimate calls. This type of attack is referred to as a TDoS or Telephony Denial of Service attack. These attacks are ongoing. Many similar attacks have occurred targeting various businesses and public entities, including the financial sector and other public emergency operations interests, including air ambulance, ambulance and hospital communications.
Scheme: These recent TDoS attacks are part of an extortion scheme. This scheme starts with a phone call to an organization from an individual claiming to represent a collections company for payday loans. The caller usually has a strong accent of some sort and asks to speak with a current or former employee concerning an outstanding debt. Failing to get payment from an individual or organization, the perpetrator launches a TDoS attack. The organization will be inundated with a continuous stream of calls for an unspecified, but lengthy period of time. The attack can prevent both incoming and/or outgoing calls from being completed. It is speculated that government offices/emergency services are being “targeted” because of the necessity of functional phone lines.
• The attacks resulted in enough volume to cause a roll over to the alternate facility.
• The attacks last for intermittent time periods over several hours. They may stop for several hours, then resume. Once attacked, the attacks can start randomly over weeks or months.
• The attacks followed a person with a heavy accent demanding payment of $5,000 from the company because of default by an employee who either no longer works at the PSAP or never did.
Recommend the following:
• Targeted organizations should not pay the blackmail.
• Report all attacks to the FBI by logging onto the website www.ic3.gov
o Ensure in the title of the report you use the keyword TDoS
o Ensure that you identify yourself as a PSAP or Public Safety organization capture as much details as possible
Calls logs from “collection” call and TDoS
Time, date, originating phone number, traffic characteristics
Call back number to the “collections” company or requesting organization
• Method of payment and account number where “collection” company requests debt to be paid
• ANY information you can obtain about the caller, or his/her organization will be of tremendous assistance in this investigation and in preventing further attacks.
• Should you have any questions please contact the National Coordinating Center for Communications at
[email protected] or 703-235-5080.