Had an issue with our skinny prepaid mobile the other day. 

Have to say, skinny customer service was second to none!  They were really good, even though the mistake was ours (apparently an MMS caused our account balance to fall below the plan renewal amount , plan expired and remaining balance from the topup disappeared).    Skinny still restored our top up amount. Didn't even ask or expect that.  

I have an issue with MMS though, should be abandoned. Have now disabled it in phone settings. 

In fact, we are having general issues with text messages now. For some reason, my son cannot text me unless he is on data. If the iphone imessage fails, it does not send through as a normal text.