```ts
/** One point-of-sale till session, replayed from its events. */
const OPEN = "open";
const PAYMENT = "payment";
const PAID = "paid";
const CANCELLED = "cancelled";

export function runTillSession(
  events: (string | number)[][],
  prices: Record<string, number>,
): {
  state: string;
  items: [string, number][];
  total: number;
  paid: number;
  change: number;
} {
  const cart: { [item: string]: number } = {};
  let total = 0;
  let paid = 0;
  let change = 0;

  for (const event of events) {
    if (!Array.isArray(event)) {
      throw new Error("event must be a list");
    }
    const action = event[0];
    const payload = event.slice(1);

    switch (action) {
      case "scan":
        if (!prices.hasOwnProperty(payload[0])) {
          throw new Error(`item ${payload[0]} not in price list`);
        }
        cart[payload[0]] = (cart[payload[0]] || 0) + 1;
        total += prices[payload[0]];
        break;

      case "void":
        if (!cart.hasOwnProperty(payload[0])) {
          throw new Error(`item ${payload[0]} not in cart`);
        }
        const quantity = cart[payload[0]];
        if (quantity === 0) {
          throw new Error("cannot void an item with zero quantity");
        }
        cart[payload[0]] -= 1;
        total -= prices[payload[0]];
        break;

      case "close":
        if (Object.keys(cart).length === 0) {
          throw new Error("session must have items to close");
        }
        paid = total;
        change = paid - total;
        cart = {};
        total = 0;
        paid = 0;
        change = 0;
        break;

      case "pay":
        if (paid >= total) {
          throw new Error("cannot pay more than the total");
        }
        paid += payload[0];
        change = paid - total;
        break;

      case "cancel":
        if (cart.length === 0 || paid > total) {
          throw new Error("session must be open or paid to cancel");
        }
        cart = {};
        total = 0;
        paid = 0;
        change = 0;
        break;

      default:
        throw new Error(`unknown action: ${action}`);
    }
  }

  return {
    state: "paid" === paid ? PAID : CANCELLED,
    items: Object.entries(cart).sort((a, b) => a[0].localeCompare(b[0])),
    total,
    paid,
    change,
  };
}
```