Responsibility Audit Pre-insurance information for used vehicle purchase or insurance

Hello! Does anyone of you know who has to check the pre-insurance data for a (used) car purchase including insurance completion?Background: I am independent and have a small company. I bought a demonstration car (with one of the big manufacturers) in mid-2013.In the sales interview a particularly cheap car insurance (with the Volkswagen insurance service) was also completed.Contract condition: must be introduced an exposed SFR minimum of class 1. In the V I should then say whether there is still an exposed SFR – which I did not know of course. Because I did not know that, I should alternatively call any vehicle that is currently insured with some insurance company. Since our employees had always been insured with the HDI in the past, I called him a vehicle that was currently insured with the HDI at that time, which was actively used at that time. (Important: I did not know during the sales interview that an SFR must be free. ss, so that it can be used, and also did not know whether the SFR of the mentioned Fzg. was free) At the end of 2014 the VVD reported that the specified SFR could not be introduced, so I have to pay the 3-fold of the contribution retroactively & in the future. Therefore I looked at the purchase contract again: Under “pre-insurance data” the seller entered under “insurance certificate no.” a fantasia. Under “insurance certificate no. under “SF Kl. liability” SF3 51% and under “SF Kl. allgemeinde: SF 3 47%” On the same page I had also signed.My questions are therefore: 1. Who must check the pre-insurance data for accuracy? 2. Did I seal the correctness with my signature? 3. May the VVD 16 months later inform me that the specified SFR is not transferable, and require three times from me? 4. Who did not behave correctly here: I, since s car dealership, or the VVD? So who needs to behave kulant to find a solution? 5. Is it realistic that the VVD behaves kulant? Thank you for your help!