SMS's do not get delivered completely

This is probably the tenth time I complain about this. Then it gets corrected for a while. And then the problem starts again. 80% of the times my mother sends me an SMS, it does not get delivered completely. Jyst a few words ending the SMS and in brackets \Receiving text". Both her and my contract is in my name. I literally only het 2 out of every ten sms's sent to me. And I have to pay for them all!! """