@Nineli Lashkarashvili Could you please try to delete your workspace from the CLI?
az ml workspace delete [--all-resources]
[--no-wait]
[--output-metadata-file]
[--path]
[--resource-group]
[--subscription-id]
[--workspace-name]
Installation of the Azure CLI is easy and once you install and authenticate with az login
Azure ML cli is an extension of Azure CLI which is installed when you run azure-cli-ml
If this fails to delete your workspace a support ticket might be required. We can help you with a one time free ticket if the above method does not work. Thanks!!