Phone/post claim

I could never cope with an online journal so today I had to do my universal credit claim using Relay U.K. (I can hear but not speak). I asked them to communicate by post as a reasonable adjustment but said if they need to phone me to use Relay and that phone calls make me self-harm. The man then said he had to speak to a manager because he didn’t want them phoning me. Now I’m really anxious because I don’t know what will happen. My support worker told me to ask them to use post so she can help with any letters. Is this really unusual? I didn’t tell them they can’t phone me. I just wanted them to know that it always makes me self-harm so if they can do it by letter that would be better. What will happen now? I’m really anxious about it. I told them that my support worker says she can help with sending ID if they need it.