We bought a used car in Japan, and it took the dealership 2 months to deliver

My wife and I went to a Mazda U-carland (U-carlands are Mazda dealerships that sell used Mazdas) to buy a car for her. The salesman must have been at least in his 50s, and he was very inexperienced. He didn't seem to know much about the car. He didn't even know what was needed for the deal (for example, the inkan, the jūminhyō, etc.). From our perspective, it looked like it was his first sale. Anyway, from the very start, he said it would take about 4 weeks for them to deliver the car, and I have read on the internet that it shouldn't take more than a week or two if you're buying a used car here, but we took the car anyway. After the contract, several delays happened, and I'm going to write all of them here so that anyone buying a car here doesn't make the same rookie mistakes we made.

1. To rent a parking space and get a parking certificate, I contacted my landlord/property management company. Although I'm the tenant, the apartment is in my employer's name, so they told me to make a request through my employer. I told my employer, who called the property company, and they prepared the contract for parking and the parking certificate, etc. They sent the documents to my employer, who handed them to me. Imagine the delays. The New Year holidays didn't help. It took about 2.5 weeks for me to get the parking documents.
2. During that time, the salesman contacted us twice because there were some errors in the car contract (errors for which he was responsible). Each time, he sent the new pages via letter packs. We signed and sent them back using the letter packs he provided. That happened between weeks 1 and 3.
3. My wife made an error while filling in the bank information. She put down the wrong branch number of her bank account. The error was only detected around week 5. They sent documents (again), and she had to sign them and send them back.
4. Around the same time, the salesman contacted us again, saying there was correction tape on the date area of the parking certificate. Again, I told my employer to contact the property management company to issue a new document. As usual, it took them 5 to 8 business days.
5. The new parking certificate had the wrong address. They put down the same address for the parking spot and the apartment. Technically, they are at the same location, but in Japan, empty lots don't have usual addresses like buildings. They have some kind of official numbers and use a completely different system. For example, a building's address looks something like 1-1-1, but the parking lot address looks something like 1-1234. You can't search those addresses on Google Maps (I didn't know that). At that point, my wife was furious. She called the property management company directly and said a property company should know these things better than us foreigners and told them to "send the correct one this time and send it today." They apologized to her, and we received the correct document the next day. My wife said to me, "If something else happens again, let's cancel the car."
6. And something else did happen. Around week 6, the salesman contacted us again and told us that the residence record (jūminhyō) we submitted displayed what's called a 個人番号 (My Number). If you issue a jūminhyō at a コンビニ, there is an option to choose whether to display these 個人番号 numbers or not. It turns out you must not display these numbers in almost all situations. We didn't know that, so it's on us, but what's infuriating is that the salesman or any other person at the dealership who handled the document could have pointed it out right away.

So, I hope you can learn from our mistakes. We're finally getting the car this week (this is week 8). Hopefully, nothing more happens. The upside is my wife gets a very decent limited edition SUV with leather seats (she LOVES the car) without paying a premium (it's a Mazda, afterall), but the downside is we had to deal with these underpaid sloths. So, you get what you paid for, I guess.