Huge issue with iMessage

Hi,

Sorry if this belongs in a different section. I'm having huge issues with iMessage and am extremely aggrivated with apple.

I switched phones to a non-apple product but all my iPhone contacts are still defaulting to iMessage.

Here are the steps I've already taken:

Contacted apple support and they unregistered my device from iMessage (said it would take a few hours, it has been four days)

Unregistered the device myself online

Changed the password to my apple Id so iMessage couldn't authenticate

Reset my device and all other apple products I have.

Had friends delete my contacts and any previous messages I have with them.

Contacted my carrier and they confirmed that there was nothing they could do, it was an apple issue.

One forum said if I have them manually send a text (when iMessage says not delievered) that after a few tries it will begin to default.

#1 - this hasn't worked, it doesn't default

#2 - this is impractical, I have 2000 contacts.

Extremely aggrivated, and will not be recommending apple products to anyone else.