I joined a new company 7 months ago, as part of their offer my salary was to increase by £3000 after completing a 6 month probationary period.
After successfully completing this period my pay for last month didn't reflect the increase I was expecting. I contacted HR about this on Thursday but they were out of office until Monday, I got a response on Monday saying they would look into it and ask senior management and I sent them the offer letter I originally received from them that confirmed the pay rise.
I have heard nothing back since then, I don't understand why because this is a straight forward situation as far as I can tell. How long is a reasonable amount of time to wait to hear back before following up and how should i follow up in a polite but firm way.