DWP 'phoned me, apparently. re. ESA Assessment

I attended an ESA WCA thing a couple of weeks ago.

Today, the DWP phoned both my landline and my mobile, about twice each, but I did not answer. Much later, when I looked at my mobile phone, it showed missed calls, BUT it also showed a text message from the DWP saying that they were bout to phone me and that the phone call would show up as withheld or "starting with 0800".

But I did not see this message till evening, when I look at the mobile, so now I had better reply to them. What should I say? The thing is, I don't like phone calls but I suppose I have to allow them to phone me. Must I really? Am I allowed to say that it would be better to write? I'm quite worried about this and don't know how to reply to them.

Ah, not going to be good news then. Thank you very much for responding, though. I think I rather hope they write instead, but I am very grateful that you answered.

i hope you have a nice weekend.