I was unable to cast spells that i had plenty of mana to cast, he had played terror of the peaks and when my turn came i tried to cast Lullmage's Domination to gain control of the terror of the peaks, he had 15 cards in his graveyard which reduces the casting cost of lullmage's domination by 3 colorless mana so to take terrror of the peaks i needed to have 3 blue mana plus 2 due to the casting cost reduction when i cast it and chose that X=5 i clicked auto pay and it told me i had insufficient mana so i tried to use Bloodchief's Thirst to destroy it casting it for its kicker cost and yet again i was told i had insufficient mana. i tried multiple times to cast them and kept receiving the message, yet somehow i had enough mana to cast in Lurrus Dreamden(3mana) and 2 merfolk windrobbers(2mana total). i had a total of 3 islands 5 swamps and a temple of deceit. so even without the mana reduction of LullMage's domination for him having 8 or more cards in his graveyard i had enough mana to cast it because it costs 3blue mana +X (so for terror of the peaks i needed 8Mana total to cast without the reduction) i had a total of 9 Mana 4 of which could be tapped for blue, i am Very upset and displeased with this game as of right now.