I received an mail confirmation from pwc no offer letter.

I received an mail confirmation from pwc not offer letter? They asked me to submit the salary slips and supporting document, after that I got a call after 2 weeks for the negotiation and they offered me then 10.5 lpa and

when I asked about the joining bonus she said that she will confirm by Tommorow,

then constantly following up & a call and they are ignoring me for over week now

what should I do should I contact my interviewer

Or

wait for the HR to confirm for the joining bonus