If you own your phone and not planning to get a new phone any time soon, then check any prepaid plans.
https://www.koodomobile.com/en/prepaid-plans?INTCMP=KMNew_NavMenu_Shop_PrepaidPlans
You can check public mobile too. ( Their customer service is only through online tho)
The $20.00 talk and text plan (after autopay discount) that you are referring too was a Black Friday/Boxing week special that is long gone. Perhaps you will see it again next Black Friday, but that is a long wait. This plan does not come up very often.
If you’re going to be on no data, have your own phone, and don’t need international roaming, you can consider swithcing to prepaid. Right now there is $19 with unlimited Canadian calling and 500MB of data. It’s the cheapest unlimitedtalk option. If you’re willing to pay for 360 days at a time, the $149 option with unlimited talk, and 30GB of data, which works out to something like $12.50 a month. They all come with data anyways, but they’re a lot cheaper and include unlmited talk.
I am already a Koodo client. I just want to lower my plan to zero data. I have 20. I want to lower it to zero. How do I do that?
Someone from Koodo please explain this to me
Hi there,
You would switch it by doing so in self serve. As Dennis shows in his screen-shot and Russ has explained, the pricing you're looking for is not available on the postpaid service. Currently, it would be $35 before an auto pay discount, again, as seen on Dennis's post.
If you want that price point, as Goran and Mayumi mentioned, they have the option on koodo prepaid. You would just have to switch to that service. I suggest you go over their posts again as they describe everything you need to know. If you don't know how to change your plan in self serve, feel free to follow the steps in the link to do so 
https://www.koodomobile.com/en/help/changing-your-rate-plan