These drainage job are expensive. They did not want to provide a quote over the phone -red flag! If you have cement storm drainage they will want to replace-period. It is very hard to clean cement drains so replacing is the best option but it is expensive-beware. Get a at least 2 quotes, don't be fooled by a "red hot deal" if you take their quote today. If you agree to have "only" your corner drains dug up and replaced, it is just a *** job as you will need to replace everything between them anyway, so its just BS to suggest you can only do your "corners" without replacing all old cement/clay drainage tiles. Get a written quote BEFORE you start.