Who called from 5622770651

Just received 5 messages in Spanish from this number on my cell phone.  I don't speak spanish.  I don't pay for the phone, my son does.  What do I did to keep him from being charged for the text messaging?

4/29 Last night received another 6 messages in spanish from this idiot.  I don't understand whoever it is not realizing sending to a wrong number.

5/178 Text messages in Spanish in the last 20 mins.  I don't speak Spanish and want to stop this A from messaging my cell phone.  How do I stop this??