Please be alert to any received calls on your mobile from 015 or 013 number prefixes.
To cut a long story short, IF you answer these calls, there can be no voice and connection cuts in 3-5 seconds.
It is clever SCAM....DO NOT answer, or, just reject the call.
My experience was that the two times I innocently answered, I thought was just a wrong number...appeared to be from a home phone.
When my Movistar account suddenly dropped by 10 soles after the first time....ummm, I thought it could be a Movistar issue.
The second time, I was quite annoyed and investigated the number on the Internet....many folks had the same experience, but from various last numbers after the 015 and 013...BUT one comment said that her phone credit was greatly reduced.
Sooo, I checked my credit again...sure enough, another 10 soles ad evaporated. Mind you, I had not made any outgoing calls since my re-charge.
Seems to be a clever SCAM...so please be alert. Not sure if it's happening outside of Lima.
Hope this helps others....as my dad once told me "learn from the mistakes of others, as you don't live long enough to make them all yourself "!!