Invoice paid twice

Hi, 
I wanted to change from monthly to annual payment. There was no way of doing that once I had signed up for montly, so I had to cancle and then sign up again. 
Seems like something was wrong, as I got to pay for a yearly subscription twice. 

If you can solve it, I would rather not get a refund, but rather just have paid for two years if that is possible.

Kind regards
Thorbjørn