Force specifi delivery on COD payment

Hello i would like to force shipping method change when customer choose COD payment.

I know that i can made COD avilable for that specifi shipping but i want COD payment to be always visable in case to do that i need to add all my shipping options to COD payment. When i do that customeres will be able to choose cheap shipping which shouldn’t be avilable for COD, so i want to force shipping method change to COD shipping.

My customers are older ones and thay don’t see COD shipping, so when thay dont choose it thay can’t choose COD payment and i loss them.

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