waiting 5 months now

i bought a ford bantam bakkie in November last year. when i got the car the remote central locking did not work. i informed them that i would buy it but they would have to fix the key. the sales person juan agreed. since then and now they have send tech out 3 times to fix the key. still no result. they never follow up. i have to keep phoning and ask when is this going to be sorted. i feel i have been very patient. but this is unacceptable. they were very quick to sell me the bakkie but no after sales service.