Did they bring the soap when you called to ask?

While there are a very few DC taxi services which take callouts, the wait is often 30-40 minutes. Hence the advice to wait 10 minutes at one of the busiest cab stands in DC was solid advice for which you should thank a savvy desk clerk.

As an alternative, DC has Uber Taxi which simply adds $2 to the meter. But, you must summon that from your smart phone.