Not able to redeem code for 1600 points which I received with Microsoft Order

Since that would not be a Rewards program offer, Rewards support would not be able to assist. Keep in mind that Microsoft points were discontinued in 2013 so it could be expired. You'll either want to reach out to the place you got the card from, or try
posting here with the error message/code you receive when you try redeeming the code - https://forums.xbox.com/en-US/forums/0d7dc557-ea57-4938-a0e8-7f05d0a019fe_e2e46498-6402-4c6a-b958-69...

I ordered from Microsoft Store also. I received the game, but no codes for the pre-order bonuses. (Alyx Brand + Hammerburst) or the 1600 points.

On the other hand, I received my code in email, and I was able to successfully redeem it. I received my 1600 point card yesterday. It's possible that the offer said one per person. You'll need to talk with Microsoft Store customer service though.

Sorry to hear your troubles. It looks like you've been provided with a coupon to use on the Microsoft Store website rather than an digital code for 1600 Microsoft Points to be used on Xbox. The coupon will apply a discount when you purchase 1600 Microsoft
Points from the retailer's website. You must place an order for a 1600 Microsoft Points card and then enter the coupon code which will give you a 100% discount (therefore giving you the points card for free). If the coupon code is still not working when you
place an order then you must contact the retailer to discuss the discount being applied to your order as they are the ones who generated the coupon. They may no longer have the 1600 Microsoft Points card in stock either, so you will have to contact the retailer
to work out the next step for you to take advantage of this offer.

I have checked the billing website, especially the "Points" section and it lets me see any transfers to or from microsoft until April 2011 and none of the months from April 2011 - March 2012 show a transfer of 1600 ms points to my account. I supposidly received
an email with a code which I then redeem for the points but that likely went to my junk mail and was auto deleted after 10 days. As they were never claimed, it should be easy enough to be sent another email with a code?