I've just bought an LG Optimus L5 and I've come across the following issue:

While I have my mobile data connection turned on, people can't call me. Tried with two different SIMs, and as long as the data connection is on, whoever tries to call me gets the standard carrier response indicating the number is unreachable. I can call other people from the LG without any issues. As soon as I turn the data off, I can be reached without any issues.

Is this a common problem for this phone? Anyone else came across it/has a solution?