No response to missing issues in a part-works subscription

I subscribed to a part-by-month build- Build the Jaguar E-type. For over two years I having been trying to get missing issues and continuation ones out of them. They have changed owners and are now trading as econovix. Still no success. I have just written them a nine page letter listing almost all my previous correspondence and hope this might elicit a fresh response... hopeful I remain.