USCIS archived my file before it was completed

[LARRY1001]

I just found out yesterday why i have been waiting so long for my oath ceremony letter.....I had my interview on April 4th and up till now had received no oath ceremony letter.......finally after many phone calls to the uscis and visits to the local office they told me my file had been mistakenly archived away in Washington like everything had been completed.....now i'm told it'll take 3-4 weeks minimum to get my file back to California and who knows how long after to schedule my oath ceremony.....has anyone else had a similar experience.....I'd really appreciate any info......Thankyou