Project delays can happen for a number of reasons. Sometimes creators hit unexpected roadblocks while they’re working on their project, or underestimate how much time it takes to complete a project and fulfill rewards. However, creators are expected to communicate these setbacks and keep backers in the loop along the way. The updates section on a project page is the best place to check on a project’s status.
If the creator hasn’t posted an update, you can send them a message to check in and see how things are going, or post a comment on their project page.