Receiving same text over and over

I have a Samsung T100 mobile which has been working up till now with no problems. Now when I receive a text from someone I know, I may receive it another 5 - 10 times at varying times and days later. This doesn't happen for every text I receive. I have also had it happen on texts which show that a text I sent has been received. Can anyone help me with this problem or is that the end of my phone?