Tier-4 (Doctorate extension) visa application was refused

Dear friends, my Tier-4 (Doctorate extension) visa application was refused by home office on 09-12-2014 (applied on 27-11-2014). According to the first refusal letter, the reason mentioned for refusal was the following - 'insufficient points in maintenance(funds) section'. The detailed description state that I haven't maintain £1640, for 28 days from 30-10-2014 to 26-11-2014; however, 2 days later, on 11-12-2014, HO asked me to submit further supporting documents (My first bank statement was print-out of online statement supported with letter from bank). I submitted my original bank statements and USS pension fund documents (Previously, I was working at the University for 2 years as a research assistant(Tier-2) and then registered for a PhD). On 19-12-2014 I received an email correspondence from an officer who was evaluating my application, demanding for the latest pension documents (dated Dec-2014), in email he clearly stated that he will accept those(USS pension fund) documents as evidence of funds. But now (on 21-01-2015) I received another letter (fourth letter) from HO stating that they refused my application because I didn't maintain funds from 31-10-2014 to 27-11-2014 (again changed dates). All the dates and reasons given for the refusal are contradictory, I received 3 letters and the dates in refusal reasons are different, it seems like the officer who checked my application is randomly stating reasons for refusal. I had maintained £1640+ from 29-10-2014 to 26-11-2014 ( I had leave to remain until 30-11-2014 so I posted my application on 27-11-2014). I don't know what to do now, I was suppose to join for an internship with Network Rail in January 2015 (since I didn't had any documents, they refused me). I am planning to go for administrative review, I kindly request everyone here to provide valuable advice. Thank you very much!