Refund subscription of Linkedin

Hi there .

I want refund my premium subscription amount (Linkedin) .. I don't want to use this premium .

Even I could not get any notice before this payment.

I have already ask this question to Linkedin

But They told me ask this problem to Apple customer support

I cancel and turn off the auto-renewal charge on my Apple account already

Please figure it out and help me get refund about this fee.

Many thanks

Best regards

Ben Jang