Karicare Toddler Gold+ Formula

We got this brand this week as it was on special and our normal toddler gold formula was sold out. Elle has 1 or 2 cups a day and started having it on Tuesday. As of this arvo she hadn't done a poo since Mon and was walking funny and crying because her tummy hurt. She's been saying "poo coming" for 2 days but nothing happened. TMI but when it did come, it was so huge she bled and I happen to know that she hasn't yet passed it all and is holding onto the rest. :(

The formula said it "now contains prebiotics which will make your childs stools softer and more regular"!!

Since nothing else in her diet has changed, would you agree it is probably the formula? Is there anything I can do i.e. get a refund or anything?

Neither Conor or Nyah did well on this formula at all. We had alot of problems with constipation. Could she is experiencing the same problem.