If your pudding did not thicken you may not have let it set long enough. It will take at least 2 hours to thicken however it may take longer. I like to let mine set overnight and enjoy it the next day. Another issue could be you didn't stir the chia seeds well or submerge them into your liquid all the way. To troubleshoot a runny chia pudding add more chia seeds stir well and allow it to set until thickened.