I have had similar problems with Toyota. I ordered a RAV 4 Excel 2WD on September 22 last year and not long afterwards the RAV fell off the Motability website! I got onto Motability and they said that they would still support my order and the AP was about £2300 (war pensioner). The RAV 4 reappeared and the AP had risen to £2800 ish and Motability said they would support the original AP as my order was extant.
Just before Christmas my dealer informed me that Toyota was going to cancel my order and the reason was that the RAV 4 was getting a minor facelift and all fleet cars that did not have a build date were to be reordered. Of course I was pissed because the RAV 4 excel was nowhere to be seen on the Motability website but I was given some assurance by my dealer that they fully expected the RAV 4 to reappear in Q1 2022, which it duly did.
On Jan 1 the RAV duly reappeared and lo and behold the RAV 4 Excel was being offered with either 2WD or AWD and the AWD had an AP of about £1900 whilst the 2WD had an AP of about £2800. No brainer, on Jan 6th I ordered up an AWD Excel and Motability sent me the approval letter with pin etc for the AWD. However, my dealer tried very hard to fulfil the order but Toyota prevented it being ordered (I knew there was a mistake with the AP but got in quick enough for Motability to approve the order). My dealer ordered me a 2WD RAV 4 Excel on the 7th January weyhey. Expected delivery sometime in October!! Soon afterwards the RAV 4 disappeared off the website again!!
Anyway, I kicked up about the AP rising to £2800 ish and big Toyota and Motability have decided to honour my AP at £1900 ish so all in all after all the hassle I am currently happy. With the contribution of £250 from Motability once the car is delivered and the return of my old car in one piece my new car should hopefully cost me buttons weyhey.