Was 250 had 130 left to pay gone up now through balliff to 440

Had a fine for not paying for tv licence thought I'd paid it all off but I hadn't collectica are now involved telling me I owe £440 they've passed it on to ballif as I didn't phone them before the date on the letter which came a month after the date I was to call them . Phoned the bailiff he wants all the money up front by end of week my partner is blind with Tumour I'm his carer I explained this to him he said he would come out and check but wants 100 pound when he calls and then week later wants £200 week after that £140 . I can't afford to do that he said he can get lockSmith to change my locks to gain entry if I dont answer the door I'm willing to pay the amount just can't do all that amount every week I've offered him £100 a mnth till it's paid he was having none of it what do I do I'm under stress with my partner being not well I dont want bailiffs upsetting my partner demanding money when they visit any advise please