The fact is that the contract has been in place for years and Iran has been pushing Pakistan to finish the project so that they can help their own economy by importing cheap Iranian gas for just as long. The thing about paying a fine is also not a new thing and as I said to this day Iran hasn't enforced it even though legally speaking Pakistan should have paid the fine 7 years ago.
There is enormous pressure from the United States not to complete this pipeline. With Pakistan being so dependent on both the United States and Saudi Arabia for their funds, at this point they can't take any concrete action on the pipeline. If the pipeline was completed on time, it would have been mutually beneficial for both the countries (Iran and Pakistan), but none of the politicians in Pakistan has the balls to stand up against instructions from the US.
For Iran, the ultimate aim was to extend the pipeline to India, which would have assured it of stable revenues. Pakistan would also gain in the form of transit fees. But then, the India-Pakistan relations worsened and they remain at that state for more than a decade now.