I was able to get a refund processed for storage I accidentally purchased by calling the above number ^^.
It did take me three calls because the system is fully automated and it was difficult speaking an answer to any of the automated questions that would actually get me to a live person - the first time I was automatically hung up on for not replying; the second time I couldn't get past the automated system. The third time I was finally transferred to a live person; and after being transferred to a second live person it took about 20 minutes to get the refund processed. I'm hoping it goes through and will be watching my credit card statement closely for the next week. Apple will call me back a week from today to ensure the refund was processed.