I have a close friend who is Jewish. Sometimes she tells me things that I doubt, but she says she would never lie to me as Jews do not lie and it would jeopardize her relationship with Hashem. Yet sometimes she will “lie” to help e.g. today I saw her and she told me to go home and rest and she would pretend we had been together if work had asked where I was. How does that fit with her insisting Jews do not lie as it is a sin?
As a rule, it is true that Jews are forbidden to lie, as the verse states, “you shall distance yourself from falsehood” (Ex. 23:7).
However, there are circumstances in which the Talmud writes that it is permitted to “change one’s speech,” the classic example being bringing peace between people. The Talmud proves this from the fact that G-d himself “changed His speech” in telling Abraham that Sarah had laughed at the prospect of giving birth at her own old age, whereas in fact she had laughed at the prospect in view of her husband’s old age.
I do not know the circumstances of your friend’s possible lie, so cannot comment.
Certainly, it is forbidden to swindle somebody, the more so where the is some financial gain from it.