Been charged twice for apple music subscription

I want to get a refund as I have been charged twice this month for my apply music subscription. I have always had this set up, but by accident my son registered to apple one. We managed to cancel this and got the refund for it. We then realised we no longer had the apple music subscription and so registered again. Thing is I have now been charged for this on the 2nd Feb and the 9th Feb. Need to be refunded £9.99 but not having the subscription cancelled. Thanks in advance