This scam has been around for ages, where people give missed calls from 'premium' numbers in Nigeria, UK, Pakistan, China etc, and then when unwary customers politely return those calls, they are charged @ premium rates(for example Rs 10/minute in India where average tariffs do not exceed Rs 1/minute), or worse the scammer uses their own talk time to try hoodwink them into another scam like the infamous lottery one etc. Therefore, before dialing back a number which is unfamiliar, take the effort to Google it once(or call only after you have done so). The results may astound you, since some customer out there would have flagged this number after getting scammed. For example-+923057636540.
Your telecom operator will most likely not do anything, because nothing illegal can be proven and then you DID make the call out of your own free will. So take care