Delete the trailing sign "/ /" & merge number with "/" and cancel merged cells

Hi guys .
I search for way to arrange data as I put it in LIST sheet.
in SH1 sheet data are not arranged .
I need fixing somethings :
1- any merged cells in any column should be cancelled
2-in column C there cells are divided for each individual cell like "/" & A4710 as in example . I want merging
and write some words " SALES INVOICE NUMBER" to become SALES INVOICE NUMBER / A4710 as in LIST sheet
3-if there is two from "/ /" should delete one of them to become one "/" when merge with number
4- should add TOTAL word in last row for column C .
thanks in advance