Sending texts to a landline (home phone) is a 3rd party (TeleMessage) service which incurs additional cost, 25¢ (see here). If the text is undeliverable, then it would cost 20¢. You can get more information regarding the service here.
If you would like to prevent sending texts to a landline, you would have to contact TeleMessage directly and ask them to disable the service for your number.
Hope this helps
I emailed email@example.com
Please block "Text to Home Phone" service for mobile telephone number XXX-XXX-XXXX and XXX-XXX-XXXX, service provider is Fido.ca account number XXXXXXXXX
They replied with