Openserve doing change of ownership without consent

I have been with Openserve since September 2023 and the tenants in the flat next to me app**** for fiber. When openserve activated their fiber, they canceled mine and did a change of ownership on the line for them to have internet. I have been struggling with this issue for a week now to get sorted out and it is still not done... there is no way of contacting them to get this sorted out and they just don't reply to any emails sent to them.