Aringoth,
This document acknowledges the sale of Goldenglow Estate and all property, assets and materials contained within. Payment of the property has been made in full by Gulum-Ei as an agent on behalf of the buyer. All dealings with the Thieves Guild in Riften is to cease immediately. To deter any possible retribution for this act, you are to take immediate steps to protect our assets in any way you see fit. I think you'll find that the Thieves Guild is far more bark than bite and will likely avoid Goldenglow Estate rather than thin their already dwindling numbers.
Good luck and may this be the start of a long and lucrative partnership.