Dla to pip

Hi I'm a new member on here, just had the paperwork/ work to change from DLA- PIP, Sent off October 19th, Recieved a letter back from capital to say they are assessing my case, then yesterday I got another letter to day to say I have to attend a face to face medical, miles away from my home, all this paper work totally confuses & stresses me, out, I have limited mobility problems, & multiple health problems including hip Dysplasia, kidney cancer, fibromyalgia, rhumatiod arthritis, osteoarthritis, Sjorgrens, pernicious anemia , low blood pressure, & many more, the Macmillan benifit adviser came out to help fill in the forms & requested that I got a home visit, but this has not been noted,& they want to see me Nov 21st @ 9am I have since check my appointments & I am at the hospital the same day having a CT Scan, X-rays, & bloods so I phone them up to see if they could do a home visit & to change the date, the man who answered said that he couldn't find it in My note, & it was advisable to keep the appointment, I explained that I have to get my scans done & can not be in 2 places at the same time again I asked if I could have a home visit because I was in hospital October 31st having a hand operation so can not get about or do anything he said he would be sending another letter out in the post any advise on what I need to do for this assessment would be much appreciated, thankyou