Phone support is currently unavailable, unless you have a payment device that comes with 24/7 over the phone support you wont be able to reach square support for now.
https://uk.issquareup.com says payments should be running fine, try connecting with sales/support for further information on https://squareup.com/help/gb/en/contact they should be able to help you with the issue. If this helps, mark it as best answer to help others find a workaround faster in future!
