Forza 5 glitched

Hello,
I havn’t played forza in a month or two and when I went to play it today my cars would not load, as in there was this grey filler car where my car should be in the show room and the track, if I went into uprade the game would crash. its as if the cars are corrupted. Can someone please get back to me with an answer asap and also I don’t want the first answer to be reinstall it as I downloaded it and it was painful enough the first time. Its on xbox one btw.
Thanks to any helpful people in advance

How could I get in contact with someone official, cause I tried emailing them but nothing

First try any system maintenance you can, then try reinstalling, then once you’ve tried everything else If you still want to contact someone you can contact T10 as per the instructions in the FAQ stickied here http://forums.forzamotorsport.net/turn10_postst6805_Forza-Motorsport-5---Game-FAQ.aspx.

also where can I find the day one car pack to reinstall, cant find it anywhere

Use the link Windswept Dragon provided.

I cant find a topic in the frequently asked questions regarding reinstalling owned dlc that doesn’t appear in the xbox store

Highlight Forza 5, hit menu button (3 horizontal lines to the left of the X button), manage game, select the DLC in question and install.

Have you viewed game details it should be in a section called ready to install

It ok, I don’t know what the problem was but the ready to install section was not there before. thanks