"What you said is that they lied / lie to me?" Should we agree the verb tense, "lie" in -that clause with the verb tense, "said" or "is"?-- If they still lie now, use 'lie'. If they lied only in the past, use 'lied'.
And don't forget this option: What you said was that they lied / lie to me?"--In this case, you can use 'lie' or 'lied'