Static IP Addresses swapped on two locations

I have a client with two locations. In Feb 2016 they were sent two fritzbox routers by 2 Degrees, one for each location.

I pick up one of the fritzboxes, rock 3k down the road to location 2 - install it and off we go.

Statc IP addresses set up on both boxes, VPN, remote access etc all sorted so the two locations work with interconnection for SIP, VPN, Security, Sahred files etc.

Loc A - IP ends in 237

Loc B ip ends in 253

Four days ago - Location B goes down. Ont has a red LOS light. After a very frustrating discussion with a support person whose sole aim in life was to tell me I am wrong about everything (including being allowed to discuss the account) we get an Enable Tech sent out. Thankfully it did not take 8 business days as help(sic) person said it might.

Fix the cable (broken at box on street) and site B is working. however simultaneously Site A stops working.

Long story cut short - 2Degrees denies doing anything.

Yesterday get user to pull power plug from router in site A and after restart it is back on the internet.

However VPN, RDP, Remote aceess to security etc not going. Access to cloud services limited by source IP also failing.

Discovered today site A now has static IP ending in 253 and site B ending in 237. (swapped ip addresses)

2 Degrees says I must have swapped usernames (exactly the same as each other), swapped modems nope -as I haven't been on site and the only people who have logged into the routers in the last few days have been two degrees.

I did note to the tech three days ago their records for the serial number for fritzboxes were swapped with Loc A as Loc B in their notes.

The two boxes picked up IP addresses 2 years ago. One of them had 600 plus days uptime. We have had the same settings for two years and now it turns to custard.

2Degrees says not their fault and they didn't change anything but we certainly didn't. I have logs from three independent servers (mail, cloud services and SIP provider) showing devices in site A coming from IP address ending in 237 until yesterday when it changed to 253. ditto devices from site B (ending in 253)

Any ideas what may have gone wrong?