I used it today with a different sign up, it had a maximum of 3000 redeems.
Yes but you can use that specific code once only. All email addresses that registered on takealot and had not ordered anything before got such coupons. In the email it says "*Coupon valid until 11:59PM, 14 October 2018. One coupon per new customer, T&C's apply.
Limited to first 3000 redemptions. New customers only."
This means the first 3000 people that got such codes will be able to use it.