Refuting a Christian claim about the word "Allah"

I would like your help in refuting a Christian claim as this has been bugging me for a while now Is the epsilon truly more fitting of the first letter of the word "Allah" (as pronounced in Arabic) when when translated to greek from arabic or would it be an intermediate . Also wouldn't starting with epsilon render the pronunciation of the rest of the word incorrect as in Arabic the second alpha isn't really 'a' it's more of an o and the L's are pronounced differently and the xhi at the end would become silent. I would be grateful if you could respond to this as both Christians and Muslims use this word to refer to God. https://christianforums.net/threads/666-is-allah.102890/