TL note page 1: you can, in fact, TL this to "hello" (no need to say it twice), or "earth to [whoever you're talking to]". You absolutely don't have to operate within the confines of the textbook definition of もしもし in this context.
Like... yeah, don't cop out right away. Appreciate the attempt, but you've got resources out there (other groups, for starters) that can give you better ideas than Googlations could possibly ever provide, and I encourage you to seek them out, rather than assume you have to go things alone.
As a final note, you don't have to, and shouldn't, TL 100% literally. Leads to things like translationese (e.g., TLing every さすが to "as expected" -- gross, don't do this) and worse, wapanese (such as this situation, when you couldn't think of a way on your own of how to express what was being said based on context).