Quick to take money with no after sales service

Good day Nissan I called head office "call was dropped" maybe you can assist me with direction I purchased a nissan NP350 with approx 18000 km on the clock 6 weeks ago as Nissan could not supply a brand new vechile as ordered there was no stock available I noticed oil drops under the vechile near the selectors and contacted Thomson Nissan in Port Shepstone who requested I bring the vechile in which I did I was told it looked like a seal that must be replaced. This was ordered and I took the vechile in today.. only to be contacted to be told that the gearbox has a problem. The gearbox must be sent to Pinetown so they can assess the problem 2 to 3 days then they will have to order the parts or replace or what ever. This could take a further 2 weeks. This is a new vechile still under warranty. This vechile is a commercial vechile and my only source of income is transporting children to school. For me to be unable to do this for 2 to 3 weeks would mean I will loose my income totally. Nissan does not offer any vechile that can lesson the load there attitude is only once they cannot have parts or a new gearbox will they offer some vechile. I have been operating for 8 years I sold my old 16 seater as I felt as I transport children it was getting old and I must have a reliable safe vechile...... this has proven to be a fallacy as its the 2nd time there is a problem 1st time being a " recall" seal in back axle had to be replaced Please i need guidance as to what I am supposed to do close my business as i won't be able to service my parents as 3 weeks will kill me financially please help I have left a call back on head offices number please action this message urgently.