ESA payment less than it should be

My ESA fortnightly payment was £489.30 (support group plus severe disability premium) I’ve begun the migration to UC and completed all my tasks for it. I was expecting my interim ESA payment before I’m advised what I’ll be getting (on the 26th May, with payment commencing at the end of May), but I’ve just received an ESA payment of £314.55 ! I tried asking on my journal why it was less, and was advised that as they were UC, I’d need to contact ESA for an explanation. I’ve been trying the number and have been put on hold for an agent for about 45 minutes now! Anyone know why there may be a shortfall? 😬 I will advise their response should I ever get through to an agent!

They finally answered the phone after I’d been holding for an hour and twenty minutes! 😲 (for future reference to anyone, they close the lines at 17.30, but if you were on hold before that time: they’ll continue answering the held calls until 18.30)

I was told the shortfall is due to it not being the full two weeks and that it will be made up by my UC payment which starts on 8th May 😬