My ex currently has custody of our teenage son. Our PP states that all non-emergency medical decisions must be jointly agreed upon. Another point of importance for this question would be that I am liable for 67% of his medical costs.

He initially lived with me after the separation. I had to move to another state for work and after a year here he did not like it so he moved back with his mother. His mom does ok financially, but does not make a great deal of money. So when it came time to purchases like glasses, I would often just buy him a cheap pair to lower the burden of cost on her. I would often purchase many separate pairs, but would only send her a bill for a couple different pairs so her out of pocket cost was always less than $20-30. All of which I would communicate upfront with her about before purchasing per the PP.

Recently, she sent me 2 separate bills for multiple pairs of glasses totaling over $1000 saying she expects prompt payment so she does not have to file contempt charges. I responded in telling her this was a non emergency medical decision and I need to be consulted before purchases can be made. She cannot unilaterally decide to spend large sums of money knowing I have to foot the majority of the bill. She responded by saying that if she does not receive my payment in full by EOD, she will be filing paperwork with the courts.

Being that this, in my understanding, clearly outlined in the PP, I do not feel as if the charges are fair and I should not be liable for them. Do I have legal standing here to fight this or am I SOL?