following review my PIP stopped no decision letter received

I've been on PIP and ESA Support for 6-7 years as I have multiple chronic conditions. during these years I had 2 successful PIP assessments.

recently I had my last PIP review (over phone) ,I followed the guide from this website but they decided to stop my PIP.

the way I found out was from a letter from ESA,telling me that I will receive less amount (nearly half) ESA support.

I have not received the PIP decision letter.and according to ESA the decision was made over 2 weeks ago.

I only received a text and a letter from PIP saying they have all the information needed to decide about my PIP.

so I called PIP after waiting about an hour,I was told that the review was not successful but they said they've sent the letter weeks ago and I should have received it by now.

the perosn on the phone said they will send another copy which can take 10 days to arrive.

I asked if it will arrive in time to request reconsideration and they said they expect reconsideration request within 1 month of the decision date but if it's later than 1 month it's still okay.

is this correct?
is there anything I can/should do other than waiting for the second copy of the letter?