Bicycle is Having a hard time Shifting -- especially gears 13 and 14 21 speed commuter bike. Raleigh 2011 brand.

After my gear shifter cable was broken, I took it into the shop to get it fixed. (4 days ago). Ever since, when shifting, it takes forever to actually shift and often does quite 'violently'. Shifting way past the trouble gears (past where I can currently handle) or way lower solves the problem. But that's not a good solution obviously.

Is there anything that I can do to fix this problem? What did they mess up at the bike store?
The cable needs adjusting.  A new cable will tend to stretch and go out of adjustment, so they should provide a free adjustment after replacing it.