Webafrica LTE: False Advertising

Signed up for Fixed LTE (CellC) with Webafrica. This was the wording in the email I received from them:

We now offer both RAIN and Cell C coverage. Visit our LTE at Home page to find out who covers your area. • No Contracts • FREE* router (packages over R530) • Or order the SIM only and we will credit your account with up to R500

Go on, you know you want to!

COME AND GET IT... RIGHT HERE, RIGHT NOW

*Router is free to use. If you cancel your service within 12 months you will have to return it in its original packaging or purchase it.

CELLC is about to cut off the LTE service and Webafrica now requires you to move over to Telkom LTE. Because of this i have decided to cancel the my service with Webafrica. Because I am cancelling my LTE service with them they require me to return the router. I have been with Webafrica for 20 months and they still require me to return the router. When I sent them a screenshot of the original email and highlighting the wording where it states " If you cancel your service within 12 months you will have to return it in its original packaging or purchase it." and asking them that this clearly means I should exempted from having to return the router. The reply I received was that they can see how the wording can be confusing and they agree that wording isn't correct and they apologies for this but I still need to return the router as the router belongs to them and it is only free to use if I use their service. How can you apologies 20 months later only when cancelling that you used the incorrect wording and no amendments or corrections were sent out to your customers bringing this to their attention?

My question is: "If you cancel your service within 12 months you will have to return it in its original packaging or purchase it. " So basically the same thing goes if you cancel the service after 20 months. Why mention a timeline at all if the router will never be free?