not having data plan is reason for motorola cliq acting up?

[youknow.]

ok i brought a brand new motorola cliq from someone that had internet so went they reseted the phone it gave it to me it worked for about 2 days until problems start occuring it was fine until yeserdai when he stop sending texts and keep sending them back to me and btw i have the wifi on at my house so i restarted the phone to factory settings and now it wont read my sim card is it the sim card or is not having the data plan is the reason why