För att hon hade slagit ett fynd med honom. Citera Wikia :
By the time the Black Pearl reached the coast of Shipwreck Island,
Barbossa stood on the ship's forecastle, conversing with Tia Dalma,
regarding their bargain. The mystic accused him on intending to betray
her and therefore reminded him on that he was brought back from the
dead by her power, and also, demonstrating her abilities by briefly
decomposing Barbossa's right hand, cautioning him of his fate should
he fail to keep his end of the bargain. Barbossa in turn reminded her
that she, secretly the goddess Calypso, was the one who needed him;
she resurrected Barbossa so he could help retrieve Jack Sparrow from
Davy Jones' Locker and summon a meeting of the Brethren Court, since
only the nine Pirate Lords had the power to free Calypso. To avoid the
risk of the goddess reaching an accord with someone else, Barbossa
ordered Pintel and Ragetti to lock Tia Dalma in the brig. Barbossa
remained on deck, glancing at his right hand while contemplating his
debt.
Wikia ger också den relevanta dialogen:
Barbossa: "I do not renege on a bargain once struck. But we agreed on ends only.
The means are mine to decide."
Calypso: "Caution, Barbossa. Do not forget it was by my power you return from
the dead. Or what it mean if you fail me."
Barbossa: "Don't you forget why you had to bring me back. Why I could not leave
Jack to his well-deserved fate. It took nine Pirate Lords to bind you,
Calypso. And it'll take no less than nine to set you free."
Även om du är ärlig samma Wikia-sida står det något i motsats till detta i ett tidigare stycke:
With the death of Hector Barbossa, the Pirate Lord of the Caspian Sea,
came a prime opportunity. Tia Dalma/Calypso needed all the Pirate
Lords in order to assemble the Brethren Court, so they could release
her from her human bonds. And so, through undetermined circumstances,
she resurrected Barbossa from the dead and tricked him to summon a
meeting of the Brethren and retrieve Jack Sparrow, who was taken to
Davy Jones' Locker by the Kraken.
Det verkar konstigt att hon måste trick Barbossa för att göra vad hon behövde när hans uppgift var ganska specifik: rädda Jack Sparrow och sammankalla alla Pirate Lords.
Således är de exakta omständigheterna i deras affärsuppgörelse oupplösta.
Varför de andra piratherrarna inte kände igen henne verkar vara ett plotthål också. Calypso verkar inte ha befogenheter att ha förändrat sitt utseende, så hennes uppfattning som Tia Dalma verkar fläckig.