Need URGENT help regarding international student health insurance!

Hi!
I am a 35-year-old American who is supposed to be going to Vilnius University in Lithuania this autumn for my first year in one of their bachelor’s degree programs— that is, if I am able to meet the requirements for a temporary residence permit in time.

One of the requirements is obtaining international student health insurance, but I am having trouble understanding:

• which various plans are good ones that cover pre-existing conditions and the regular treatment of them
• what the hell a 6-12 month notice period is
• how the hell one can get around that, if they can at all.

Can anyone explain this to me and help at all?

I have emailed both VU’s admissions office and also the woman in their international relations office multiple times within the last few weeks about this, and no one has responded to me yet.