Take it back in, hopefully the repair guy warranties his work, mine does for 6 months, so there's no charge if you have to bring it back.
I have a Kenmore Elite that I'd never had serviced for like 20 years. A couple of things were annoying me so decided it was time. When I got it back, suddenly the tension seemed to be off so I took it back. What we discovered is, I had worn out the plastic foot. I didn't know you could wear out the feet, guess that's why the metal ones are so popular. So, a new plastic foot and she's humming along!