A month ago we were in exactly the same position as you are now. The calls/letters will continue, we are still getting some and our meeting was on 14th March. Your situation sounds almost identical to ours. The people on the phone have their job to do but unfortunately they do not seem to be in the know about the IVA process, most of them do deny all knowledge of your IVA. I just told them to contact my IP as I knew they did have all the details and wished them good day.
Stay strong and you will be OK.
Good luck for the 10th.
"Life is too short to wake up in the morning with regrets. So love the people who treat you right, forget about the ones who don’t and believe that everything happens for a reason. If you get a chance, take it. If it changes your life, let it. Nobody said that it’d be easy, they just promised it would be worth it."