No feedback and response on damaged handset (Samsung SM-Z400)

The Samsung SM-Z400 was delivered to my house address on 09/06/2017. The handset was faulty from the start. The deal was done by Thandeka Mdlovu. The package promised was R129.00 a month. I receive accounts of R150 and more. After going to Riverhorse vally twice, they eventually admitted that the phone was beyond repair. I dealt with Zipho Mbethe. I got a waybill number (R09CWR ********** ********** 67) and then I was told to ring ********** 622 where I got no service after speaking to Siphelele. She could not assist me. I was told to ring ********** 667, then was advised to ring 808. Nonsikelo referred me to ********** 667 again. She gave me a ref. number ( ********** 41154) they advised me to ring ********** 241. I spoke to Akashni. She gave my a wrong number and advise. i phoned the call centre. Precious said I was at the wrong department. She advised me to ring ********** 667 (who I rang before. I spoke to Nontadazo. I received a message on my old Nokia which I am still using which said query has been resolved. A few days later I spoke to Thembe ( ********** 667). She referred me again to 808. I spoke to Gregory at Umhlanga Rocks. He said he would Thandeka to phone me and promised to contact me to find out whether my problem was solved. He never contacted me. On 13/10/17 I held on for 32 minutes after ringing ********** 622. I rang again and spoke to Tsepo. He told me wrong department and he would put me through to Thandeka. I held for 22 minutes and gave up. On 17/10/17 Seleka Mhlontlo referred me to repairs department. ( ********** 0349) Farida Suamado she wanted IME number and she will get MTN direct to phone me. !8/10/17 - Nobody has contacted me up to now. My request is - Replace my phone or give me another phone of the same value. PLEASE HELP!!!