Multiple Xlookup or Vlookup help PLEASE!

Hi all, really hoping someone can help with something that I think should be simple....
Attached is sample of the type of spreadsheet I need to use monthly...

Sheet 2 - I need to have a list of customers names and their account handler in column B and C respectively.

Sheet 1 - I need to input monthly data.

I just want the HANDLER column C on sheet 1 to show which (if any handler) is assigned to the customer, using info from sheet 2.
I think I should be using X or V lookup which I am generally ok with doing but I cannot work out how to get it to search the multiple values.

Any help would be so much appreciated!