They keep calling me and they never say anything either

I got two calls from 786-248-5996 today.  I answered the second call and it was my ex-wife calling for my daughter to talk to me.  She said she was calling from her phone, but her phone is a 239 area code.  When I call back, I also get a recording saying "your call cannot be completed at this time."

I do not know who the caller is but when I try to call it back, I get a message that the Network is too busy to complete my call, try your call again later.  This is not a typical Carrier message and seems to be generated at the receiving end.  They obviously do not want incoming calls.