I'm not receiving the full 50% credit back on eligible expenses from daycare providers. I spent $9882, but am only receiving $3920. Shouldn't I receive $4000

Not necessarily.  There are income thresholds that also apply.  The 50-percent amount begins to phase out if your adjusted gross income is more than $125,000, and completely phases out if your adjusted gross income is more than $438,000.

In this article, the IRS provides the following information concerning the Child and dependent care credit changes  IRS Expanded Credits for 2021.

Child and dependent care credit increased for 2021

The American Rescue Plan increased the amount of the credit and eligible expenses for child and dependent care, modified the phase-out of the credit for higher earners and made it refundable.

For 2021, the top credit percentage of qualifying expenses increased from 35% to 50%.

In addition, eligible taxpayers can claim qualifying child and dependent care expenses of up to:

• $8,000 for one qualifying child or dependent, up from $3,000 in prior years, or
• $16,000 for two or more qualifying dependents, up from $6,000 before 2021.

This means that the maximum credit in 2021 of 50% for one dependent's qualifying expenses is $4,000, or $8,000 for two or more dependents.

When figuring the credit, employer-provided dependent care benefits, such as those provided through a flexible spending arrangement (FSA), must be subtracted from total eligible expenses.

As before, the more a taxpayer earns, the lower the credit percentage. But under the new law, more people will qualify for the new maximum 50% credit rate. That's because the adjusted gross income level at which the credit percentage is reduced is raised substantially from $15,000 to $125,000. AGI is the amount shown on Forms 1040 and 1040-SR, Line 11.

Above $125,000, the 50% credit percentage is reduced as income rises, plateauing at a 20% rate for taxpayers with an AGI above $183,000. The credit percentage level remains at 20% until reaching $400,000 and is then phased out above that level. It is completely unavailable for any taxpayer with AGI at or above $438,000.

In 2021, for the first time, the credit is fully refundable. The credit is claimed on Form 2441. Also, see Publication 503 for details.