The appellant, Tubestone (Pty) Ltd, imports tyres. It subscribed to an integrated industry waste tyre management plan (WTM plan) administered by the respondent, the Recycling & Economic Development Initiative of SA NPC (Redisa). The plan was promulgated on 30 November 2012 under the National Environmental Management Waste Act and required tyre producers to pay a waste tyre management fee. The fee was set at R2.30 per kilogram and was to be reviewed annually. Tubestone paid the fees for four years but stopped paying between October 2016 and January 2017. Redisa launched proceedings to recover R2,479,335 in arrear levies. In response, Tubestone raised collateral challenges, alleging that Redisa failed to review the fee annually as required, making the fees unlawful. The court had to consider whether Tubestone's delay in raising these challenges should prevent them from being entertained.