Possible tethered cord in spina bifida

My 23 year old girlfriend has spina bifida and was diagnosed with and surgically treated for tethered cord at age 3 and 17. Because of misdiagnosis in the past, she has suffered from irreparable neurological damage in her lower extremities e.g. she cannot feel her legs or her feet (despite these challenges, she's learned how to walk without the use of braces). For the past three weeks, she's had symptoms of tethered cord that she has previously experienced such as frequent urination, the sensation that she has to urinate but can't, and yesterday afternoon she started complaining of lower back pain. We went to the hospital and they checked her blood, determining there was nothing wrong with her kidneys. Apparently the neurology department didn't think there was cause for concern and told her to come back if she experiences pain in her legs (even though she's stated multiple times that she can't feel them) and weakness. What should be done and how soon should she consult a different medical professional? Is she in danger of more irreparable neurological damage if we wait until tomorrow (considering today is a holiday)? Also, was the neurological department negligent in not seeing her?