Success Cases
congstar Chatbot Advises on Prepaid Top-Ups
congstar advises prepaid customers in its chatbot on the right top-up option. Around the clock, no waiting, built by the marketing team itself.
Goals: Make prepaid simple without loading the hotline
congstar is Telekom Deutschland’s independent brand for fair mobile plans on the D network. More than 7 million customers rely on the Cologne-based provider, which passed one billion euros in revenue for the first time in 2024 with a team of around 300 people.
Service is not a side note for congstar, it is brand core: ranked first for customer service by Handelsblatt in 2026, test winner in the connect customer barometer 2026, and named fairest mobile provider by FOCUS MONEY eight years running.
That is exactly where the challenge sat. Topping up prepaid credit sounds trivial, but it is not: app, store, direct debit or automatic top-up, plus the question of which option fits your actual usage. Customers who have to read that on a web page drop off. Customers who call tie up a hotline meant for complex cases.
Results: A 54 % interaction rate instead of a dead end
congstar extended its top-up page with a chatbot on the LoyJoy platform. Instead of a table of options, a short conversational type test asks a few questions and recommends the right top-up method, including the direct path to complete it.
54 % of opened chats led to an interaction. Customers get a recommendation instead of an overview, around the clock and without waiting.
The conversational type test is deliberately designed as a small game, the “top-up quiz”, and an NPS feedback field at the end provides continuous quality assurance.
What mattered most to congstar was speed. The team built the dialog itself without coding and could adjust it at any time, with no IT project required. That is the precondition for improving service experiences iteratively instead of rolling them out once and then administering them.