Phone breakage is a very common occurrence in the Ellipsis world, I guess.
Introduced back in Rin's cameo in strip... 4 I believe, Rin had a habit of referring to herself as "Rin-chan". She's attempting to kick this habit and occasionally slips up. Although, technically, she's just saying "Rin" instead of "Rin-chan" now, but I transliterate it as using personal pronouns for simplicity's sake.
It kind of sounds like I'm scanlating an original Japanese comic, heh. I'm trying to make this as "authentic" as a gaijin can make it so I have to think from a (probably incorrect) Japanese perspective!