Ive had this loads of time, currently ive 990,000 miles and next week do a LCY
Segment putting me almost on the million.
Pity the mil is with several airlines.
I'd say 10% of those ive had to chase up, send off a ticket receipt etc etc.
in general i find it takes a few weeks but they always pay up and credit as it's bad for future PR
The worst was moving from the US to the UK, I had to transfer my NWA to KLM, NWA transfered them but KLM didnt credit them.
After 6 emails, to and fro, cc'ing both airlines with all the replies each airline constantly declined responsibility, KLM even said NWA were lying in their email in one reply. I even arranged a conference call between both airlines to resolve it, both declined. Eventually I called a newspaper and the miles were credited next day with an apology.
For this reason (and problems in the past) I only have 1k of my miles in KLM (which were mostly in NWA)
So far in 2008 45 flights and Gold already. JFK, IAD, LGA, SIN, HKG, NRT, AKL, PPT, LAX still to book ! Home Airport LCY