刚签了买房合同,现在不想买了.BUILDER不肯退earnest money,还威胁要SUE我们.

我们看中了一幢新房子,和BUILDER谈好了价钱,请人做了INSPECTION,结果RADON超标.我们想退出.结果收到了这样一封EMAIL,大致如下:
Please refer to Paragraph 4 regarding earnest money which clearly states
that if the offer is accepted and Buyer fails or refuses to close the
transaction, without legal cause, the earnest money shall be retained by
Seller for damages the Seller has or will incur, and Seller retains all
rights to seek other legal and equitable remedies.

Also Paragraph 13 indicates that Buyer should make a written objection to
any problem revealed by his inspection which the Buyer has not done.
Further, the Seller has the option to remedy the problem. The Buyer has not
given the Seller this option.

A radon level of 5.2 is easily remedied and is in no way the basis for
termination of the contract. Not only does the Seller have the right to
retain the earnest money, he has the right to sue the Buyer for specific
performance. The Seller has been damaged due to the time the house has been off the market, and the fact that he lost another buyer when he accepted this purchase agreement.

We expect the Buyer to continue with the purchase of this property
大家给出出主意,我们该不该请律师? 应该怎么办?
谢谢先.