Calories amount changes on device and app

[Blerinab]

I usually burn around 1800-2000 calories a day, I try and workout 3-4 times a week and on other days I'll walk.
Yesterday I did around 6600 steps and burnt 1900 calories.
Today I went on 2 walks, first one in the morning was over 7700 steps, I had burnt 1200 calories by noon, and an evening walk which was around 2500 steps. For the day I did over 12000 steps but at 11pm it's telling me I've only burnt 1500 calories for the whole day! How is that possible? I was active throughout the whole day too. Only 300 calories for 11 hours? I burn more when I sleep!
When I looked at my calorie breakdown for the day on the app it looked like my big morning walk hadn't even been logged so I added it manually and saw it updated the calories.. then they went back to a lower number. It's quite frustrating to work so hard and not have it tracked. 

Moderator edit: Subject for clarity 

[RicardoFitbit]

Hi @Blerinab, welcome to the Community Forums! Sorry for the delay in responding.

Thanks for bringing this to our attention and for all the details that were shared in your post, I understand how frustrating this matter can be for you. Our Support team informed me that they already provided you assistance to resolve this situation. That said, I recommend you to contact them back if you require further assistance or if you have any additional questions about the outcome of your case.

I'll be here if you need anything else.