Poor quality tyres on generator

Purchased a brand new 5.5kW generator of which the tyres perished in just 6 months. The generator is stationed in a locked store and probably moved 50m during this whole time. The tyres are made of very bad quality plastic disguised as rubber and just started coming apart. When I complained I was told that they are deemed to be to be consumables and would not be replaced, This would hold water if the quality was acceptable and were actually used which was not the case. The Consumer Protection Act states that products that are sold must be \fit for purpose"which these tyres were clearly not. At the store I was told that this is a frequent problem. Eventually I spoke to a person named Stoffel who eventually conceded and undertook to replace the wheels with \""hard rubber\"" wheels. To date nothing has happened. """