Cannot access Linode via LISH/SSH due to memory issues

My website has been down for awhile and I am out of thoughts as to how to get it back online. I'm pretty certain the issue is memory based, but at this point I can't even get into the Linode to figure out how to fix those issues.

An attempt to login to SSH via FileZilla provides a connection time out. I can log into LISH, but I get several out of memory kill process lines and then it logs out. We even bought more memory and rebooted the Linode, but to no avail. Tried a restore to the backup from yesterday, but that did not fix the issue.

If I can't get into my files or the node in any fashion, how can I resolve this problem? I'm really at a loss at this point and any help would be greatly appreciated