Can I legally move if he doesn't file a motion with the court within 30 days from date when I hand delivered the letter?

I am legally required to provide my children's father with a 45 day notice prior to relocating out of state. I started discussing the matter with him in November 2016 via phone calls and text message. We met on December 5th and I gave him a letter covering the requirements of what I needed to include regarding relocating (I gave the court a copy of the letter and thought I would be able to sign something reporting the notice was given and have the 45 days start. They filed the letter in our divorce file but I never sent anything certified and he later refused to sign the Admission of Service). We met again on December 11th to talk with the kids. Kids said they wanted to move and he said he would send me a proposed visitation to counter what I included in my letter I had I given him on the 5th. He told me and my 12 & 13 years old kids that he would allow them to move with me. Since then he has refused to talk to me about this. He has refused to sign an Admission of Service and while he won't say "yes I got that letter" he isn't denying it; he is just avoiding responding to anything about the move. He is now saying that he never agreed to let the kids move with me and that he doesn't agree. The fact I gave the court the letter, have all the text messages, and he verbally approved this move in person to me and my children count at all? This is and has been time sensitive; I'm selling my house and need to be out by the end of January. I no longer have the 45 day timeframe to restart after he receives certified mail. I am primary custodian and we share legal custody. He has the children a whole 50 days out of the year - this is only due to his refusal to take additional time I offer him. I don't want to do something that will jeopardize me having custody, such as moving to other state and getting charged with kidnapping.