Being overcharged when purchasing x-box Gold as a gift

My son asked me to buy him an x-box gold subscription as he saw that there was a deal on so that we could pay £6.99 for 3 months.

Bargain I thought, and I signed into Microsoft using my ID and went to buy the 3 month subscription. I saw that it was indeed only £6.99 (brownie points for not being conned by my son!)

I clicked on the buy as a gift, and the price went up to £15.99 WTF?? It must be a mistake I thought and when my card is charged I will only be charged for the £6.99 as advertised if you were to buy the subscription for yourself. Nope I was charged the full
£15.99

Come on Microsoft you have to be consistent in how you charge for things, you surely can't penalise people for buying products and services because they are a gift?

Has anyone else been subjected to being overcharged in this way?

I tried to contact Microsoft support but was sent into a loop of their chatbots and never actually got to speak with someone, hence my question on here to see if anyone else has experienced this, and also to see if Microsoft monitor their community channels
to respond.

:)