Intermittent packet loss & high latency intermittently

My daughter is attending Georgetown University online and needs to be in a virtual classroom. Her grades depend on it. During her first semester which started January 6, she noticed she was losing her connection. We didn't think that much of it, and she would log back in. However, in April, she had to give two presentations and during those presentations, she lost her connection and the instructor and class was unable to view it. She thought it was her computer. However, after the school's IT Department went into her system and reviewed everything, they determined it was our internet connection with the "above issues." Last week I contacted a tech at Cox through a chat room. He said he would send a signal to reset my gateway (which I purchased from Cox -- A Cisco DPC3825 DOCSIS 3.0). He never followed through with me to see if the issue was resolved. Now today, it happened again! My daughter's 2nd semester starts tomorrow. I need to resolve this problem ASAP!! Thank you for any assistance you may have!