Sum of HLOOKUP matrix

Hello!

I am trying to make a formula that makes a SUM of all identical values in a HLOOKUP formula (or maybe something different/easier?).

It's a bit hard to explain, so I attached an example sheet.

I want the formula to count the number of times a customer no. appears, then return the sum of the value next to the customer value.

In the attached file, the orange field next to "Customer 1" should be 100, "Customer 2" should be 130 and so on.. The matrix is ongoing, so it has to count all of A:B (unless there is an easier method).

Source language of the formulas in the attached file is danish, but I hope that it will translate it automatically.