Repair your substandard equipment

I reported a fault with a vehicle tracking system, the TAG has stopped working. They should have picked this up... I sent an email on 28 Feb, and they sent me a repair notice a while later, they have no idea how old the unit is because they ware talking about age and warranty - its only a few months old... They said they will contact me.... I sent a reminder on 4 March nothing to date. Oh, and if they do not call me I must call them WHY??? I told them!!! now I must call them to remind them!!! Really pathetic.