Asda cancelled my order!

Asda said thay I reached my goal weight and they don't think I should be taking MJ anymore. And I was already on the maintenance and going down with the dose. Currently 15mg and ordered 12.5mg. I've tried with Numan but my BMI is normal so I can't get it. What now? Go cold turkey from 15?! Its been only 9months. Anyone has gone cold turkey? I am stressed that I will put it back on! Any if the pharmacy prescribes MJ for maintenance?