How can I obtain a letter confirming the cancellation of my old passport after losing it to get a Malaysian entry stamp in my new passport?

Anyone from UK here had to get a Malaysian entry stamp put into a replacement passport after losing the old one. They won't do it without police report. The police won't give a report without a confirmation letter from embassy confirming old one cancelled and new one issued. High commission said they couldn't do it. Helpine directed me to phone a UK office who directed me to passport office who said they couldn't do and directed me to back to the UK number, this loop traveled several times. Who the hell am I supposed get this letter from . 🫣