Specifically, the UOKiK has ruled that the payment of an invoice does not automatically mean the consumer consents to an additional offer.
The UOKiK says it initiated an investigation into Multimedia Polska in July 2013 after analysing media reports and notifications from subscribers.
The investigation showed that in the period July to November 2012 the operator sent a leaflet to subscribers informing them of a new offer called multiPower that doubled their internet speeds for PLN4.99 a month.
The service was automatically activated for each subscriber for a free, two-month period.
Following on from this, subscribers received an invoice for service plus an additional charge for the unsolicited package.
In the small print, they were informed that payment of the total amount would be treated as acceptance of the offer.
Customers who did not wish to receive the additional service had to make their own calculations or contact the operator to cancel it.
The offer was addressed to almost 200,000 subscribers, of who 70% accepted it.
Multimedia Polska discontinued the practice in January 2013 but has not been able to escape the fine, which is not final and can be appealed in the courts.