how can I get a geek squad employee on the phone that speaks enough English to be able to understand them?

I find calling the store directly helps quite a bit, dont deal with those call centers

Call them

You can ask for a different employee who speaks English fluently.

If you are looking for computer support I suggest looking elsewhere. I was not impressed with a misdiagnosis of an issue and when the flaw with their work was pointed out a refund was still flatly refused.