If a telephone number is used illegally, the Federal Network Agency can intervene and take appropriate measures.

A telephone number may be misused if

• you are put on hold on a chargeable number and your request is not processed.
• a company only provides a high-priced number as a telephone contact for contract questions
• you receive an announcement on the telephone to entice you to call back, e.g. by telling you that you have won a prize
• you are confronted with annoying call behavior, e.g. advertising calls on Sundays and public holidays
• Confusing, missing or incorrect price information about the connection costs when dialing an expensive number (e.g. (0)900 numbers, (0)180 numbers).
• No or incorrect price information is given at the beginning of a telephone call after dialling expensive numbers or after dialling call-by-call numbers.
• No price announcement is made for the connection costs of the transferred call when the call is transferred by a directory assistance service
• No forced disconnection of the call on the network side has taken place after one hour for a call to a (0)900 number
• the addressee is significantly misled in postal advertising letters with the purpose of submitting an answer at the specified telephone number
• you receive unsolicited advertising text messages or other electronic advertising messages via messengers (e.g. via Facebook, Whatsapp, SIMSme, Threema or Line)
• you receive e-mail spam in which telephone numbers are advertised (unsolicited advertising e-mails).
• You receive fax spam, i.e. unsolicited advertising faxes.
• you receive ping calls, i.e. calls where the telephone has only rung briefly in order to provoke a callback
• calls to expensive numbers are made automatically from your connection by a cell phone or Internet dialer
• your Internet router or telephone system has been hacked by a third party and chargeable connections are being generated as a result, or
• you are billed for inexplicable items such as subscription services on your telephone bill.

Proven unlawful use of the telephone number can be penalized depending on the extent of the infringement:

• reprimand or warning,
• ordering the disconnection of telephone numbers,
• billing and collection bans,
• porting bans,
• prohibition of business models or
• switching bans.

In order to combat number misuse, you should provide the Federal Network Agency with as much detailed information as possible on the facts of the number misuse. Existing documents such as itemized bills or screenshots of websites visited should be enclosed.