I made clotted cream and tried to heat it for serving. It immediately disintegrated so I tried to salvage it by freezing it. It solidified into something yellowish and left some liquid at the bottom, just like when I made the clotted cream. Is the solid part still clotted cream or is it something else?
From your description and re-reading the instructions for your version: yes, what you had on top was still clotted cream.
They liquid on the bottom should be whey, which gets separated from the rest during the clotting-process. Re-heating did start the same process you used originally, and left-over whey separated again.
You made butter. Unsalted butter, but butter nonetheless