Squeaky Belt

you can look and see if its just one, or three like my 98 Sonata. how many miles since it was last replaced? if any....original belt(s) ? perhaps it just needs to be tightened by the idler pulley, or the belt tensioner for each . I just had to re-tightened my alternator belt.

while they were replacing the timing belt, they "should" have replaced the water pump along with all the alternator, water & ps belt(s) it only makes sense from a labor point of view, should your water pump go, it will save you money if you had it done along with the timing belt. check your invoice, it might just need an adjustment.

If it's a belt noise and started immediately after the timing belt servicing, you should return to the shop that replaced the timing to have your car checked. I'm very surprised that the timing belt was replaced but they didn't replace a 62k drive belt (would have been cracked very badly) since they had to take it off to get to the timing belt anyway. At the very least, they should have recommended you do it.