No, you do not need a landline to connect to fibre.
ADSL uses copper telephone cables to transmit data and Fibre Internet uses fibre optic cables to transmit data.
Here is what you need to get fibre - https://help.afrihost.com/topic/fibre-broadband/what-you-need-to-get-afrihost-fibre
When you sign up for fibre, a fibre line will be installed at your home, provided that there is fibre available in your area - please check the fibre availability map.
If you require further assistance,
please send a message to our WhatsApp helpline: https://whatsapp.afrihost.com
WhatsApp Help is available from 07h00 - 20h00 Monday - Friday
or visit our Help Centre: https://help.afrihost.com/
or see our FAQ page: http://faq.afrihost.com