I'm wondering whether anyone has any experience of changing their contraception whilst they are on tamoxifen?

I currently have a mirena coil and am due to start tamoxifen next month. I am getting married in May and my breast surgeon and oncologist were happy for me to wait until after my wedding to start on my tamoxifen so that I don't have to deal with the side effects during that time. I also need to get my mirena coilf out and have it replaced with non hormonal contraception before the tamoxifen but again I don't want to get it taken out until after the wedding as if the copper coil doesnt agree with me I don't want to be suffering side effects/a heavy period during  my wedding and honeymoon. 

I tried to call my local sexual health clinic and book an appointment for removal and insertion of the new coil and the nurse said it had to come out now. She was really patronising and said that because it was probably fuelling my cancer it had to come out now. This was without knowing about my specific type of breast cancer/treatment. I explained that i had discussed it with my oncologist and she was happy for me to wait. The sexual health clinic consultant called me and then confirmed it should be coming out now and that was her advice. In the meantime I called my breast care nurse to confirm what had been agreed with my surgeon and oncologist and she confimed they were both happy for me to wait.

I am now a bit worried but ultimately am of the view that 4 weeks isn't going to make a difference and my oncologist was happy. As far as I'm aware it just needs to come out before I start tamoxifen. Has anyone else had a similar experience?