You should leave, and here is why: 1. It doesn't sound like your work was properly respected. 2. It doesn't sound like you were supported by your previous emp

You should leave, and here is why: 1. It doesn't sound like your work was properly respected. 2. It doesn't sound like you were supported by your previous employer. 3. It sounds like your new employer needs your help just as much as your former employer. 4. You committed to something to the new employer, not just to the former employer and the only one out of the three of you that is responsible for this delay is your former employer. 5. They have enough other developers, the consequences of you leaving are maybe a single extra day of development. Leave.