Pressure over Apple’s App Store practices gained steam, as messaging service provider Telegram filed a competition complaint with the European Union (EU) challenging the US giant’s commission charges, Financial Times (FT) reported.

Telegram was said to have raised its concerns with Margrethe Vestager, EC VP and Competition Commissioner, arguing Apple should open access to apps beyond its own store, and calling for a review of its fees.

The messaging company said Apple’s practices stifle competition.

In a blog, Telegram CEO Pavel Durov said Apple’s 30 per cent commission made “all apps and digital goods more expensive for you” by adding to developers costs. Combined with the price of iPhones, “you keep paying even after you have paid”, he stated.

Music streaming service Spotify and e-commerce platform Rakuten have also lodged complaints with the EU over the App Store’s alleged monopoly.

The EC initiated a probe in June to explore whether Apple had shut out competitors by mandating the use of its own in-app purchasing set-up, claims the company denied while noting its fees were broadly in line with those of Microsoft, Google and Amazon.

CEO Tim Cook this week also defended Apple’s approach during a grilling by US politicians, stating it treats “every developer the same” and its App Store rules were transparent.