complain regarding zync tablet z930

&lt;p&gt;&lt;b&gt;Location/place&lt;/b&gt;: surat&lt;/p&gt;<p><b>Name of company/service</b>: snapdeal/zync</p>Dear sir,
i had purchased zync tablet from snapdeal.com online retail store.At arriving of same tablet we found problem regading its wifi functioning. We complain regarding same on the same day of recevied to snapdeal as well as zync on next day.they given us faulty product & not taking responsibility for replacement. they suggest us for repair work,on basis of thier suggestion we sent same tablet for repair to zync service center delhi.but zync done nothing regarding problem of tablet return back to us with same problem ,said that there is no problem in it. kindly suggest us for necessary steps regarding same.