Hey D4RK-273,
Sorry to hear you weren't able to get that purchase to go through in time to finish up the collection. Just to clarify, you were trying to get additional Apex Coins at the time, and that's what wasn't going through - not the packs themselves - is that right?
Did those orders process and simply not award the Apex Coins, or did those transactions all just fail entirely?
Unfortunately, if those packs were still being purchased right up until the end of the event and that event has now ended, there's not a way for us to now make any changes to the contents from that event, nor can we grant shards for something that was not completed. Keep in mind even if purchased during the event, the packs would all have to be opened while the event is still active as well in order to receive the final event reward.
I'd definitely take a look through these steps if the payments were failing entirely, and it may be worth checking with the bank or card company as well just to make sure any additional purchases weren't flagged for security purposes as can sometimes happen with large online orders - such as the 6,700 coins would have likely been.