Spark plugs

Hello, I have the following problem : I was with my Ford for inspection, e.g. I also had spark plugs made. Be a few days it is not running properly, in the transition from cold to warm. I had the good Bosch candles with 4 contacts in before the inspection. Now they have only put in the cheap candles with 1 contact. I believe that it is because of it. Can that be? As I have also found out, there are no more candles from Bosch. Is that also correct? What kan n man make? Sincerely Red