apple music subscription + free trial

I purchased an apple music monthly subscription by accident, when I was actually meaning to get the free trial version, and that's fine. The problem is then I tried to add the 3 months trial on top of my regular subscription and it doesn't let me do so because it says i already have a subscription. Does anyone know if there's any way to fix this? it seems absurd to me that anyone can get 3 free months and I basically paid 10€ for just one.