I bought another set of this company's tires for t...

I bought another set of this company's tires for the car - premiumcontact 6 245/45/18 (summer) for audi s8 d2. Above 110 km / h the car gets into a very troublesome vibration. On old summer tires, everything is ok, also in winter. I will also add that the tires are particularly loud !! The car has two sets of new rims and everything in the suspension is good. I advertised tires at the distributor but after a few days it was found that everything with them is ok - it was found to be the fault of the suspension in the car. I wrote an email to Continental but did not even receive an answer. Although this is not my first tires of this company in the current situation I feel embarrassed approach to the customer and the quality of their new products. For future people who are thinking about buying tires of this brand, I strongly advise you to think deeply, because in case of any problems they have to reckon with the help and support is not even on the WARRANTY. Everyone is nice only at the time of sale and complaints are immaterially rejected.