data entry input spreadsheet macro - easy job

Hello, I have 10 spreadsheets with approx 6,000 entries in them, i need someone with a clever macro to delete all entries which do not have the network provider of "bt". I have included a example of one of these spreadsheets, and also a detailed example of what i want doing . Basically the spreadsheet shows a range of numbers & i want the numbers creating, and delivering to me in a huge csv file. All necessary instructions attached.