DELAY IN GETTING THE RENEWAL LETTER

[SKPPR]

HI,
I had applied for regular PR renewal, my application  was approved on 10th aug, & letter for pick up was to arrive within 4 weeks, after 4 weeks called the call center & they asked to wait for a week finally after waiting for 2 weeks I called today & the call center agent said she had no clue why I havn't received the letter yet & have asked me to wait for another 4 weeks & call back
what should i do?, is there any way to rush up things.
thanks