PIP assessment cancellation mess up

Hi all,
I received a f2f home assessment appointment for the 14th March, which I had to cancel as I had another appointment the same day at the hospital, which I had been waiting months for. When I phoned to cancel the lady searched for another appointment but didn't have any, and advised me to call back later in the week. On the 14 the the assessor called me to say he was running late. I told him I had cancelled it, and he told me he hadn't been told, and he was sorry to have bothered me. I didn't think any more of it. Last week on 25th March I called Capita to find out if there were more appointments, to be told my case had gone back to DWP. So I called DWP to find out why, he said because I missed the appointment and gave no good reason!! I explained I had cancelled it and why, and he reluctantly agreed to refer it back to Capita. They lady I spoke to to cancel it obviously didn't cancel it, and it now looks like I missed it. Today I received a letter from DWP saying they have decided I'm no longer entitled to receive PIP as I missed the appointment and gave no good reason! So I called them up, and the lady I spoke to said it had gone back to Capita along with a hospital report they received last week (no idea why they received this or from which department), and I would receive another appointment soon. But now I'm worried the letter means my current award PIP has stopped and they'll want my car back, which I need to get about as I live in the middle of nowhere, or will I still get it for now? The letter was dated 26th March,the day after DWP agreed to send my case back to Capita. I'm feeling so anxious right now, please can anyone advise me?

Thank you for replying, but the date on the letter was the day after I spoke to them?
Do you think I will continue to receive my payments? I did speak to Capita already today and they hadnt got the case this morning x

Thank you, I shall call them again

Hi Gordon,
I spoke to DWP again, the girl was incredibly rude and kept talking over me while I was trying to explain. In the end I got out of her my case is back with case manager for referral back to Capita. She said it could take 4 weeks for them to look at it.
I checked my bank account this morning, and they have indeed stopped my benefit. I now don't know what I should do, I cannot lose my car, I rely on it as I live in the middle of nowhere and cannot use public transport or taxi.