Did Gechazi say so to Elisha?
Radak: No. He said so in his heart.
What was Gechazi's complaint?
Malbim: He should have taken money. Really, one may not heal Nochrim; if one must do so, one should not do so for free 1 . Even though Elisha properly refused to accept a gift, lest he go thank his idolatry 2 , he should take wages for healing him!
This is like giving a gift, which is forbidden due to "v'Lo Sechanem" (Devarim 7:2). However, YD 158:1 forbids even for wages, and when it is permitted, it is even for free! Amidst lust for money, Gechazi erred. (PF)
What is the significance of "Me'umah"?
Rashi: It is written Chaser, without an Aleph 1 , to enable reading it Mumah; taking from Na'aman was a Mum (blemish) for Gechazi.
Minchas Shai: Mikra Gedolah is like Rashi says, and so implies Midrash Tanchuma, but in all Seforim there is an Aleph. Kli Yakar says that Chazal expounded a tradition to pronounce it without an Aleph; the Midrashim imply unlike this.