Your account cannot make this type of purchase

Hello. Whenever I try and purchase an Avatar item, I get an error message saying that my account cannot make this type of purchase on Xbox.com, please purchase on your Xbox... I was using my Xbox One S to make said purchase, so can this problem be fixed?
I have now attempted purchase on several seperate consoles to no avail, I am thinking this is a security issue but I've only had my Xbox 3 weeks and a half.

:)

 

How can I change to an adult account?

I can't purchase backwards compatible Xbox 360 games on my Xbox One, and am given the message "Your account cannot make this type of purchase from this Xbox.com. Please complete this transaction from your Xbox". As I will soon no longer have access to my
Xbox 360 to work around this issue, is there any way to change my account from a teen account to an adult account so I can make these types of purchases?

 

Problem downloading Xbox 360 game on to Xbox One

Hello, I am having a problem where I cannot download Stuntman: Ignition. I have Xbox Live Gold and for some reason cannot download it. I get the message 'Your account is unable to make this type of purchase on Xbox.com. Please complete this transaction
from your Xbox' when I press on see price. Please help.