​I didn't receive my 4,000 credits for this month at all. My balance was set to 0 as soon as the new billing cycle started, without any allocation being added.

Do you understand that we are users like yourself, and unable to access or change your account.  We can only suggest possible reasons when you have the issue, and how you might resolve it. 

It sounds like you have a full Creative Cloud all apps account.  Is that so? 

Are you able to use apps like Premiere Pro, After Effects etc. on this account?

Does it show the correct total for your plan?  i.e. 4000 (I realise mine is different)

What reset date does it show?

It’s hard to get through 4000 credits quickly just using Photoshop.  Check your Firefly history and make sure there is nothing there that you didn’t create.

Other than this, I can’t think what might have happened in a way that we as ordinary users can help you.

BTW  This is a user to user forum, although some Adobe employees do occasionally read these posts. So, the rest of us can’t access your case ID or action anything to change it.  We can only advise.

Are you logged in with the same account?  

e.g. do you use more than one email address on your computer.

What reset date is now showing?