I think that you need to get in touch with them and offer to buy that domain name from you. I believe you will run the deal

As long as YOU ARE SHURE (Check it Properly! Re;Licsense/Tax/Company/and or Patent registry offices)
That YOU Registered the Domain first(With Proof from your registrar).

AND that You don't "Damage"Their business.
And You have developed or at least a Plan/Idea for Your Domain.You are OK!

Just be firm and don't let them bully you(If all of the above is true!) And perhaps Give them the opportunity to
offer You a Reasonable Bid to buy the Domain.(In writing(Copied) and sent REGISTERED Reciept Post!)

Good Luck! Peace!

Thanks lot to all of you for your nice note and good advice.
with my Best Regards

I hope you understand that it is not oly few clicks by mouth