How can I make my daughter's dad talk to me about an important issue?

My daughter had back surgery in August. Her dad and I agreed that it would be best for her to stay with me during her recovery and has just recently been released to regular activity by the doctor.

My husband, now wants to resume our 50/50 timeshare but I have concerns about her walking 1.5 miles to a bus stop at 4 am by herself and then be home alone for several hours after school.

I have made several attempts to contact her dad to find out exactly what arrangements he has made. I mailed a letter (that my daughter said her dad never received) so then I personally gave him the letter. Still he did not contact me regarding the issue. I text messaged him to call me as soon as he could and still have not received a response. I have called him and only get voice mail.

He plans on resuming 50/50 time share beginning on Monday. I do not know what else to do to make him talk to me. In addition to my concerns about her bus route and supervision after school, I need to be made aware that next week is a midterm week and 3 days she is out of school at 10 am, she has no uniforms at his house and cannot attend class if she is not in uniform and (after speaking to the school's busing department) an new issue has arisen since she will only need a bus every other week. (If she misses 5 consecutive day they will discontinue the bus stop as she is the only one that will be picked up from there.) Ater her week with him she will miss a week when she is with me (I do not even know if he is aware of this.)

Any suggestions are appreciated!

Thank you!