Thanks for getting in touch, and a very warm welcome back to the Community Forum! I'm sorry that you're having some problems receiving texts from your some of your contacts.
Could you please confirm which mobile network these contacts are using? Do they receive any kind of error message when they try to send you a text?
Thanks for confirming this. I'm going to send you out a replacement SIM card, I'll just need you to confirm some account details via Private Message. Please look out for a purple envelope in the top right corner of your screen.