Same problem here (although only a year before right of renewal on our lease). I too am keeping copies of communication and last email was assuring them I would pay April’s rent but that we needed to have a conversation about clause 27.5 before May’s rent was due. I haven’t had a reply as yet.
I have shared this email from a coworking space in the US with the same problem as us. It gives a pretty good outline of what may be useful to write. https://dangerouslyawesome.com/2020/04/landlord-covid19
Hope it helps.