Again and again they didn’t do their part.
No matter how much you beg, please, threat, or even try to bribe.
They just don’t care. Dragging their feet and delaying the work.
But none of it is actually their fault. It is yours.
Yours because you failed to take ownership of the problem. At the 1st sign something was amiss you needed to make a change, dump them, and move on.
Don’t try to wait it out or force a solution. Listen to you gut. Either that or risk being the incompetent one.