Combining data when removing duplicates

Another approach using GROUPBY() and trimrange feature referencing full column.

=GROUPBY(DROP(B.:.B,1),DROP(C.:.C,1),SUM,,0)
=GROUPBY(B2.:.B12,C2.:.C12,SUM,,0)

LeeBrennan 

Modern Excel has so many alternatives and, as yet, little guidance concerning best practice. 

= SUMIFS(value,ref,UNIQUE(ref))

but a whole spectrum of variations is possible, including,

= MAP(UNIQUE(ref), Sumifλ(value,ref))

where "Sumifλ" is given by
= LAMBDA(v₀,r₀, LAMBDA(d, SUM(FILTER(v₀, r₀=d))))

 The purpose of the two Lambdas is to allow the sum and criterion ranges to be passed as a parameter string whilst each unique ref is passed one at a time by the MAP helper function.

LeeBrennan 

LeeBrennan 

As variant

=LET(
 ref, INDEX(data,,1),
 value, INDEX(data,,2),
 u, UNIQUE(ref),
 total, MMULT(SEQUENCE(,ROWS(data),1,0), --(ref=TRANSPOSE(u) )*value  ),
IF({1,0}, u, TRANSPOSE(total)))

LeeBrennan Hi,
i am with riny, because it is easiest and hassle free way

but i have also prepared formulation attached file

LeeBrennan I'd use a pivot table.

See attached.