My broker sold stocks in order to pay taxes on them. Now I receive a 1099-b form showing the $ amount of stocks sold. The problem is that I never received any of the funds because they were used to pay taxes on the stock. How do I clame my 1099-b? Am I double paying taxes on my stocks?

The 1099-B is a record of the value you received from the sale of the stocks - it does not tell you how much gain (or loss) you made on the sale. You report the sale of stocks on Schedule D, where you determine the capital gain (or loss) on each sale. The total of all sales you report on Schedule D should equal the amount reported on the 1099-B; that's how the IRS knows that you have reported all sales and aren't trying to hide something. Even though you never saw the cash from the sale, you enjoyed the value of the sale (as it paid off your tax liability), so you have to report the appropriate capital gains on Schedule D. So no, it's not double counting.

How much over the taxable part of the 1099 b I have to pay?

How much over the taxable part of the 1099 b I have to pay?

? Please clarify your question. The 1099B reports proceeds from your sale of stock or securites, and it should also provide the cost bais. You report both figures on Schedule D as capital gains or losses.