For refund you need to:
On one screenshot from the service of activation please fix registration process with the following information so that we can determine that the problem arose with this particular number:
If you use the app and pages with data about number, account activity and order history are different, please send a video to capture all the data. If you got a 2FA-protected TELEGRAM account, we can make you a refund only in case you provide a video proving the issue. The video should contain all of the above-mentioned details as well as the 2FA password notification. We do not provide refunds for numbers purchased via API.
Special cases you can find p. 11 rules https://5sim.net/rules.
Full information you can also find in FAQ https://5sim.freshdesk.com/support/home.
If you used the account for your own purposes, refund will not be carried out for the number.