San Van Party Pack DLC NOT Working

2 days ago, I bought and downloaded Skate 3 through the XBOX Marketplace. 
Then I downloaded the San Van Party Pack DLC, but it does not work.

In the game - in the downloadable content section, it is checked off and says installed, but there is no party play option or added content.

I have talked to multiple live chat agents, who have had me perform all of the following things (multiple times in different orders):

• I removed all restrictions from XBOX to make sure that wasn't the issue
• re-downloaded the Share Pack
• re-downloaded the San Van Party Pack
• Cleared the storage cache
• Deleted Skate 3 completely, re-downloaded, then the Share Pack, then the San Van Party Pack - still nothing.
• Unplugged the XBOX for 5 minutes, plugged it in, rebooted - still nothing.
• Cleared the storage cache again, turned off the XBOX, turned it on, re-downloaded the Share Pack, then the San Van Party Pack - still nothing.
• The agents tried activation my DLC's remotely - still nothing.

I have gone round and round doing all of these things over and over again while talking to multiple agents, and the end result is... nothing.  I still have no party play option.  Again, in Skate 3 - in the downloadable content section - the share pack and San Van pack are both checked and say installed.

Can anyone PLEASE help me?  My son saw this game on YouTube - specifically the Party Play stuff, because we play Skate 2 Party Play together all the time.  We had no idea Party Play wasn't included when you buy it from XBOX Live.  So I bought the pack too, so I'm like $27 and 8 hours of messing with the XBOX into this, and me and my son still cannot play together.

I REALLY appreciate any help or insight anyone can give me, he is super bummed about this, and I am too ☹️