Billing refund

On the evening of June 4th, I mistakenly upgraded the ZERO TRUST account to the standard version, and selected 50 people. Because I operated on my Iphone, I did not see the payment amount clearly, which caused me to pay 350 dollars. I found this problem in the morning of June 5th (within 12 hours), and immediately applied for the account to be downgraded to a FREE account. I didn’t use any of the standard user functions, I hope I can refund the $350, this is an error!
TOPIC ID: #3288348 #3288348

@cloonan please

I need some response from official!!

Sorry for the issues, I have flagged your ticket for the billing team.

I’ve been communicating with the people in the billing support, but nothing has progressed and they still tell me that I can’t get a refund, which is really frustrating.
Can you tell me what should I do now ?
It was really a big expense for me and I couldn’t finish the repayment.

@cloonan still nobody solved my request