Expert Advice Needed Mall Investors Making Offer

I really need some advice and counsel. I own a house in the uptown charlotte area. Which mean downtown they just call it uptown. 

An investment firm is building the following right beside me. They have bought all of the properties except mine. 

http://www.charlottestories.com/this-historic-1891...

I would like to present the following facts and get your opinion on what I should do. 

• The Light Rail (Metro) is being built within 1.5 blocks right next to the retail establishment. 
• I am on the east side of town the exact same thing happened on the west and the residential properties went up to around a million. 
• I can afford to hold it. I am 90% complete with a renovation that cost me about 40k. I was planning on renting it out as a residential property until I decide to sell one day. 
• I can get close to 1,500 a month and pay 400 a month in mortgage. 

Concerns:

• The investment company made an offer of 330k almost a year ago. The current residential value per comps in 155k. I said no.
• There response was they could just build around me. I have contacted the zoning board and due to my house being zoned R-8 it actually restricts the retail plan.
• One additional foot of height is allowed for each additional one foot in distance the portion of the building is from the required side yard line. Therefore it would significantly affect their plan.
• They could surround me with huge fences and building and make my property worth less. Similar to this https://upload.wikimedia.org/wikipedia/commons/e/e...
• The investment firm has threatened to surround me with a fence if I do not sell. There are no height restrictions on the fencing, just a minimum. 

Zoning Facts:

• New development across a local (public or private) street from, or abutting on the same side of a local street as, existing single family zoning (R-3, R-4, R-5, R-6, and R-8), shall have a minimum setback of (30) feet. This minimum setback shall apply only if the single family parcels front onto the same local street as the development parcel. This setback shall supersede the adopted streetscape plan.
• The height may increase one foot in height, over 40 feet, for every 10 feet in distance the portion of the building is from the required setback along that street.

Please provide your guidance. Has anyone ever held out for a better offer. What was the results? What happens if you are surrounded by a mall?

Just seems like I hold all the cards, they cannot conduct their proposed plan with my R-8 parcel in the way. The setbacks notated in zoning facts above would cause a huge problem.