Evoke HR interview questions

I got a call from them to work with godrej their client on a contact basis, after my interview with godrej they sent me an offer letter . But when I said I am unable to join one of the hr shouted me and said me why u said that u can join before ur client interview . After one week again one hr called me and asked me join , when I asked her about previous incident she said she is unaware and again asking me join godrej in 10 days with increased amount 40% than earlier offer letter. When I directly contacted with godrej they said we had not taken ur telephonic interview . So evoke hr is not trusted cmpny . They can do anything to provide resources to their client . It seems that no internal communication happens between their resources hiring team .and high compitition to hire no of resources.