In general, refunds for Azure services are subject to specific conditions. For instance, refunds for recurring charges are typically eligible within 72 hours of the start of the billing term or its renewal. However, refunds are not granted for variable charges resulting from usage, such as those incurred from provisioning resources like SQL databases.
Since your situation involves a mistake made over three billing cycles, it may be challenging to receive a refund based on standard policies. However, you can escalate your issue by contacting Azure support again and explaining your situation in detail. Be sure to mention any specific circumstances that might warrant reconsideration of the refund policy, such as being a solo developer and the significant financial impact of the additional charges.
Additionally, you can inquire about any potential exceptions or special considerations that might apply to your case. While the initial response was unfavorable, further escalation may lead to a different outcome depending on the discretion of the support team.
References: