Couldn't redeem my 5,000 gems

They would have more than 5,000 pending due to different offers they took part in or they redeemed more gems for more credits. Since credits are automatically scheduled for deposit after having 5,000 pending, there's really no way to save them up.

Deposit requests are only available when you have at least 1,000 credits pending, but less than 5,000. So it sounds like you requested a deposit and then redeemed gems for the 10,000 rewards credits. So what you got was the deposit you requested. The credits
you redeemed from the gems would be scheduled to deposit at the end of the month.

If it was for the 5,000 rewards credits, they should show as pending on the MyRewards section of the site. They would be scheduled to deposit around the 15th.

no I'm talking about MyVIP Gems I redeem 250 of myvip gems for a $5 gift card and I never received the $5 dollars

The option to request a deposit is only available when you have at least 1,000 credits pending, but less than 5,000. So you would not have been able to request a deposit at 21,000 credits. If you request a deposit and then redeemed gems for rewards credits,
the credits from the gems are scheduled to be deposited at the end of the month.

It's actually working as intended. Since you redeemed them on the 6th of this month, they would be scheduled to be deposited at the end of the month. That deposit is scheduled for the 29th.

When you redeem credits with gems, it takes 96 hours for them to show as pending in your account and then they follow normal deposit rules. Credits are deposited by the following 15th or 30th of the month after you have at least 5,000 credits pending. So
if you get to 5,000 between the 1st and 15th, they are deposited by the 30th. If you get to 5,000 between the 15th and 30th, they are deposited by the 15th of the next month.