Orange phone not receiving Vodaphone texts?

I have a Vodaphone PAYG. Am sending to an Orange PAYG and getting read receipts. Orange phone not receiving but able to send. When read receipt, arrives, it contains phone number, then it changes to the name of the recipient on my phone ie it recognises the number sending the receipt. Could my phone be blocked at the other end? Orange user has been to Orange shop with no success but is technologically not very competent so I may have to get involved. What do you suggest?