This phrase is found in Act 2 of The Importance of Being Earnest after Algernon shows up in Jack's estate in the country pretending to be Jack's fictitious wicked brother Ernest.
After arguing back and forth about Algernon's presence in the house, Jack orders his butler, Merriman, to pack up Algernon's things claiming that
Mr. Ernest has been suddenly called back to town.
While Merriman goes inside to pack, Algernon tells Jack that he is a mean liar, since he (Algernon, nor the fake alter ego, Ernest) have been "called back".
There are two ways to look at this: first, Algernon is basically challenging Jack, specifically stating that he WILL NOT leave because, literally, nobody has (or could) call him back to town.
However, the other way to look at it is that Algernon is cleverly reminding Jack that it is Jack who created the fake Ernest. In other words, that the only person who could "summon" Ernest back to town would be Jack, himself. Since Jack is not planning on going back to town anytime soon, he cannot just "summon" Ernest to suddenly show up either in person or by circumstance.
Therefore, when Algernon says that what he is really saying is that it is impossible for "Ernest" to be called back into town, first because this Ernest does not exist and only Jack could summon him (and hasn't), and also because Algernon is stubborn and refuses to leave Jack's estate.