The German Institute for Service Quality tested what was offered by 15 of the country's providers - and although things looked a little better than last year, only one firm was ranked as "very good". Eight others were said to be "good" while three were said to be "satisfactory" and another three were just "adequate".
Prices varied wildly for flat-rate deals with the cheapest price for 16,000kBits per second internet provision plus flat-rate phone coming in at around €20 a month, while the most expensive was around €40 a month.
Over the length of a two-year contract, such a difference could mean a saving - or increased spend - of €478, the institute said in a statement.
Lengthy minimum contracts and customer unfriendly regulations on cancellations were the rule, the institute said, while flexibility to help customers was generally only found when companies made exceptions.
Five of the 15 companies tested went over and above what their own rules dictated in order to help customers - granting early cancellation of a contract where the internet connection was particularly slow for example.
Kabel Deutschland was the best of the bunch, retaining its position from last year, the institute said. The firm offered generally the cheapest double flat rate - for internet and phone services, and also had the best customer service.
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