This URL where the Copay wallet used to be now just shows "We're sorry, the requested URL was not found on this server." Why was it removed? Was there a security issue? Is this going to affect the app installed on my phone?
In early September, Google removed Copay and a number of other Bitcoin wallet apps from the Play Store. I don't think we know why exactly those apps were removed, but things like that do seem to happen from time to time in the crypto world. More recently (late November), it was revealed that a hacker had managed to inject code into Copay that could steal users' wallets. I don't think those two events were related, but if you have funds stored using Copay I'd definitely recommend taking steps to make sure that your version of the software does not have the vulnerability. See here and/or contact BitPay support for more information.
But you have it installed, no? Then what's the problem?
I don't know the official line, but the github repo for it is still there https://github.com/bitpay/copay
Worst case scenario you can build it from source and recover the wallet (if you saved the private key). To do it on scratch you'll probably need a full node or someone who has one