The studio had been paying the third-party so Sniper Elite fans could "play online for free," which they've been doing for the past seven years. GLU have targeted other older titles too, like SWAT 4.
Star Wars: Battlefront, the first two Neverwinter Nights titles and Microsoft's Flight Simulator X have all lost their place on Gamespy's servers, now owned by GLU Mobile.
"A few weeks ago, the online multiplayer servers for Sniper Elite were suddenly switched off by Glu, the third-party service we had been paying to maintain them," said Rebellion in a statement. "For the past seven years we have run these servers at a cost to ourselves so that fans of Sniper Elite could continue to play online for free."
"This decision by Glu was not taken in consultation with us and was beyond our control."
The studio has tried to get the servers back up and running by the rates have skyrocketed compared to what they had been paying. As an independent outfit they simply can't afford to keep the Sniper Elite online service going.
"We have been talking to them since to try and get the servers turned back on. We have been informed that in order to do so would cost us tens of thousands of pounds a year—far in excess of how much we were paying previously."
"We also do not have the option to take the multiplayer to a different provider. Because the game relies on Glu and Gamespy's middleware, the entire multiplayer aspect of the game would have to be redeveloped by us, again, at the cost of many tens of thousands of pounds," continued Rebellion.
"While we are not happy about the situation, as an independent developer we simply do not have the resources to pay the massive costs of new servers along with redeveloping a seven-year-old game."
The reason for the upset is, that while not many would have been still playing the games online, there could have been a warning to the loyal few who remained instead of such an abrupt end.