Not enough facts are provided for a reasoned response. Discovery, while served on all parties are only ever directed to a single party. Requests made by e-mail only will not be responded to and since there is no indication as to what your requests are there is no way to state whether or not they are valid.
A proper response would require a thorough investigation into the history and background of this relationship. The information provided above is just that, information, to be used as you see fit.