The Telecommunications Act protects against unsolicited advertising calls. The UWG can open a separate review. Item 26 of the UWG Annex refers to persistent and unwanted solicitation of consumers by telephone and other distance communication. The contact history must be assessed in context.
A clear refusal, later calls, changing numbers or several service providers may together show persistence. The number of contacts alone is not decisive. The advertising purpose, clarity of the refusal, timing and internal response to the suppression request are also relevant.
The content of a call may additionally be reviewed as an aggressive commercial practice under section 1a UWG. Threats, unlawful pressure or a material impairment of decision-making can change the assessment. The communication should be preserved in its original form with a factual chronology.
If a complaint arrives, the article on a UWG cease and desist letter from a competitor or association explains how documents and possible claim directions should be separated. An injunction or interim relief requires its own review of claim, evidence and risk of repetition.