Samsung Mobile Company - DAMAGE MOBILE HANDSET

i had buy a samsung galaxy a ** with imei no ******/**/******* on **/**/**** from sristi shakti mobile shop, goalbazar, ashoknagar, pin ******, west bengal. but with in a few days i observe trouble in my handset as it was not responding properly . on **/**./**** in between a call my handset got s/off.Visited the shop, as they suggest me to visit samsung customer service. i told them about my issue, and mother board was change as per their feedback in my new phone. within * days of replacement ,when my phone was in charge, my phone gets automatically shut down and on. on **/**/**** early morning i traveled to samsung customer service centre from ashoknagar, they send me with a software update. with in a hour, when i kept my mobile in charge , same problem persist. againg i visited the centre, and they change the charging point. in that two visit, no complain no given to me . it was a waste of valuable time, money as i am depends on online activity. i asked them for a set replacement as my set had several issue . they have again suggested me to come on wednesday. now i am not happy with such brand name and demanding compensation from the company samsung. please look into the matter. aniket dey