Did you recompute your return ... are you still getting any refund anymore ? Did you apply the 2018 refund to the 2019 estimates ? If so those have changed but you will not get a refund check in that case.
Also the return had to be processed after the waiting period has lapsed so it can take longer than the stated time frame.
https://www.irs.gov/individuals/understanding-your-cp24-notice
