it’s not a cap, it’s that the monthly fee covers 120 mins. overages accrue per-minute charges, but if you’re routinely needing more than 2h talk time, jmp may not be the best answer

q21 on https://jmp.chat/faq

Every JMP plan comes with calling credit, worth approximately 120 minutes within the US & Canada, included in the monthly price. By default accounts are set to be warned when this limit is reached so no one gets any surprise charges without getting permission first. You can adjust your plan settings with the bot to raise this limit and allow your account balance to be directly billed for any minutes over the included amount.

per-minute pricing: https://jmp.chat/pricing/USD#US