HP India — cart hp 802 combo

Dear sir / madam,
i, r k ralhan purchased a cart hp802 combo from shrichand computers pvt ltd, vishal tower, distt centre, janak puri new delhi 110058, mobile numbers [protected] & 56 on 12/07/2018. The next day i installed but it wasn't working. I called an engineer, came on saturday 14/07/2018 found that the colour cart wasn't working. On sunday 15/07/2018, i went to the retailer for exchange of colour cart but he said to go to the raja garden service centre. On 16/07/2018 a rainy day monday i went to the raja garden service centre and showed that colour cart. They replied that colour cart was blank and can't be changed.
I am a senior citizens, a pensioner and also an asthmatic person.
Please look into the matter as early as possible and help me .

R k ralhan
new delhi
[protected]