Vauxhall VX1800 opel vivaro computer default reports, van won't start

Hi,
I bought an Opel Vivaro 1.9 tdci from 2010.
After 3,000 kms driving within a few days, it gave a message that there was a problem with the break and blocked the engine (slowed us down and kept on tugging the car). The nearest Opel service connected it to the computer, which showed 25 different default reports. No time to check, they deleted all reports, the car drove perfectly for another 500kms. After a month of daily use, the message came up again, but this time, the car did not want to start. Started again a few minutes later, drove with limited functions (slowed down motor and tugging). At the Opel service, they told us, they cannot connect the car to the computer (it does not connect) they cannot help. 1 km away, at the gas station, the car did not start at all again, so they towed it back to the garage. They will start "searching the problem" now for 120EUR/hour, and did not promise that they will actually do sth. The only thing they said is that the spare computer connection plug may cost itself 1,000EUR. (not yet any repairs) But 500ks ago there was no problem with connecting, and in between our little "trips to the mechanics", the car drove absolutely perfect. Please help with any useful idea! I know it can be millions of things wrong. But, perhaps someone had a similar experience. Any ideas what the problem or a solution could be?