Student Visa (F1, F2, M1, M2)

Hi, I'm posting mostly to ask about similar experiences to mine that you all might have had, and options you might have considered.

I've been a doctoral student in Computer Science since Fall 2014. Within CS, my research area is Formal Verification (not on the Technology Alert List as far as I know) and during my studies I've done three summer internships (CPT) at Intel, Apple, and Oracle, all related to my field. I returned to India in Dec 2018 for some family stuff and to renew my F1 visa which was expiring in May 2019. I was eligible for the interview waiver (i.e. drop box), but then I got three 221(g) letters. The first was through the post on 09 Jan, asking me to appear for an interview at the Mumbai Consulate. During the interview, on 11 Jan, they asked me about my progress towards my degree, my research area, and a car accident which had occurred in 2015. At the end of the interview (Mumbai) on 11 Jan, they gave me a second letter asking me to submit some documents related to the car accident. I submitted these documents along with my passport at the drop box on 25 Jan, and received the third letter through the post along with my passport in the middle of Feb. Since then, I've been writing to the Consulate often, asking if there are any documents I can provide to speed up the process, and passing on letters of recommendation from professors and staff at UT. Each time, I get the same kind of formulaic response, and when I send any documents they tell me that no documents are required. By the way, the same formulaic response was sent by Consulate staff to a US Senator from the state where I study after I requested the Senator's office to query on my behalf. To be clear, I haven't been approved, and I haven't been denied, I'm just in administrative processing.

I'm trying hard to keep my university's Computer Science department happy by taking care of TA duties remotely and writing research papers of which one has been accepted at a conference. Still, 8 months is an incredibly long time and I'm concerned the department may terminate my student status given that this is my third semester (Spring, Summer, Fall) being away from campus. Have you all ever faced such a long wait and got the visa at the end? How have you managed if your visa is denied after several years in the program? Is there any way to contact anyone in charge of this dysfunctional process? So far I have received zero replies to 3-4 registered post letters I have sent to the Consul General in Mumbai and to the US Ambassador to India in New Delhi.

Thanks for any advice you can offer.