Zero screen time. Two what should i do?

Hello doc, recently I have started practising zero screen time with my 20 month old, seems he is been addicted & showing signs to let him watch him more. We have been giving him screen at his meal times. It's been 4 months I reduced it to 1.15 hour but I need to make it zero. Because of this he is rejecting food completely, extreme tantrums & crying his lungs out for good 2 hours. Yesterday he ate nothing, only survived on water & few ounces of milk. It's been 1 day only without screen. How to manage this ? & in case he doesn't opens his mouth again for a day or two what should I do ? Reason of being this strict is his speech is getting delayed, not a single meaningful word till date which is worrisome for me. Please suggest some ideas to make situation slight better.