Can Employer Rescind Counter-Offer submitted by Legal Counsel in Writing?

I have pending wrongful termination settlement claim against my previous employer (no charges filed, negotiating). My attorney submitted a counter-offer for release of claims/final severence on my behalf in mid March. Opposing counsel gave verbal approval to my attorney on March 30, '07 and requested redlined and cleaned copies. After lengthy delays, opposing counsel submitted a written counter-offer to my counter-offer, with minor changes to verbage. This document had the same $ as my proposal. They submitted this on May 31, 2007 (in WORD format, which I thought was unusual for an attorney). They even said:

"I think you will find that the vast majority of the agreement is exactly as you proposed."

7 days later, opposing counsel left a lengthy message to my attorney stating there was a mistake and they sent the wrong attachment, and they were withdrawing the offer. The next day, they resubmitted a revised offer, 63% lower than the original, AND PRE-DATED the replacement offer to match the original offer date of May 31, 2007.

Is this legal?

I fully intended to accept the offer, but now they reduce it? The withdrawl also coincides with a former colleague who independently filed complaint at my company for similar issues against my employer.

My attorney is expecting more legal fees to renegotiate, but I don't think it's fair. I had an acceptable offer on the table, IN WRITING FROM OPPOSING COUNSEL. Why should I have to invest more money to negotiate again?

Please help!!!

[annjd]

see your other post