advice on my cat :(

so i took my little angel to be spayed yesterday morning and i picked her up this afternoon. i called to check in on her 3 times and they assured me, everytime, that she was recovering great. i had my fiance pick her up and upon returning to our home not only was she in extreme pain from her surgery(which i expected to a degree but not this much) but she has a very bad limp on her front right leg. im assuming if they gave her an IV in that leg thay they would have shaved a small patch for ir? but her leg is extremely swollen and has no shaved patch, and everytime i tried to call the vet this evening the phone lines have been busy. i plan to call again first thing in the morning, but has anyone else experiences this?