Dear Felix
I was pleased to receive and examine your proposal of [DATE, ex. June 10]. Thank you for your interest in [NATURE OF PROPOSAL, ex. rendering cleaning services at our construction sites].
I regret, however, that we are unable to accept your proposal. [STATE REASON (S), ex. Although I find the services outlined in your proposal to be of high quality, we are currently under two-year contract with Jerry’s Disposal for similar services.] {IF THERE IS A POSSIBILITY OF DOING BUSINESS IN THE FUTURE, MENTION SO, ex. After the contract expires, however, we will be pleased to discuss the possibility of doing business in the future.}
Thanks again for your proposal. I do appreciate your time and effort and wish you the best in the future.
Regards
Lydia